How to Support the Sibling of a Child with Cancer

When a child is diagnosed with cancer, the entire family is affected, including brothers and sisters who may try to understand what the diagnosis means while adjusting to major changes at home. 

For siblings, a cancer diagnosis can bring up complicated and sometimes conflicting emotions. They may be scared about what will happen to their brother or sister, jealous of the attention their sibling is receiving, lonely when a parent is spending more time at the hospital or even guilty that they are healthy. 

“These are all common and appropriate reactions,” says Marlee Speak, certified child life specialist at Ann & Robert H. Lurie Children’s Hospital of Chicago. “Having these feelings does not mean a sibling loves or cares about their brother or sister any less. They are simply responding to a major change in their family and trying to make sense of something that can feel scary and out of their control.” 

While every child responds differently, there are ways parents and other trusted adults can help siblings feel informed, connected and supported throughout a brother or sister’s cancer treatment. 

Recognize that big feelings may show up in different ways 

Children may not always be able to say, “I’m worried about my sibling” or “I feel left out.” Instead, their feelings may come through in their behavior. 

Some siblings may become clingier, quieter or more prone to acting out. Younger children may return to behaviors they had previously outgrown. Parents might also notice changes in sleep, appetite or school performance, as well as physical complaints such as headaches or stomachaches. 

Underneath those behaviors may be questions or worries children haven’t voiced: Can I catch cancer? Did something I did make my sibling sick? Why are they getting so much attention? When are they coming home? 

Creating regular opportunities for siblings to ask questions, without requiring them to talk, can help parents understand what a child is thinking and correct misconceptions before worries grow. 

Talk about cancer honestly 

Parents may understandably want to protect children from frightening information. But avoiding conversations about cancer altogether can actually create more anxiety. 

“Don’t wait to talk to kids about cancer,” Speak says. “Waiting often leads to more anxiety and stress, and they usually know when something is not being addressed.” 

Use clear, age-appropriate language and start with the information your child needs to understand what is happening right now. Words like cancer and tumor can feel intimidating to adults, but vague explanations may leave children more confused. 

As treatment continues, keep siblings updated on how their brother or sister is doing and what they can expect next. These conversations don’t have to happen all at once. Think of them as an ongoing dialogue that can grow and change along with your child’s questions. 

And remember: You don’t need to know every answer. Parents can say, “That’s a great question. I’m not sure of the answer, but let’s write it down and ask someone at the hospital.” Being willing to say “I don’t know” while helping your child find an answer reinforces something important: They can trust you to tell them the truth. 

Protect the parts of life that can stay the same 

Cancer treatment can quickly rearrange a family’s routines. Parents may spend long stretches at the hospital, other caregivers may step in, and activities can become harder to coordinate. Whenever possible, protect siblings’ everyday routines, including school, friendships, sports, extracurricular activities, family traditions and time to simply play. 

Trusted friends and relatives can help with transportation to school, practices, birthday parties or visits with friends. Families shouldn’t be afraid to accept that help. Maintaining familiar routines can give children stability when other parts of life feel unpredictable. 

Even small moments of individual attention matter. When possible, spend one-on-one time with each child or establish something predictable, such as a daily phone call when a parent is staying at the hospital. 

Help siblings stay connected 

Being included doesn’t mean giving a sibling responsibility for their brother or sister’s care. Instead, look for simple ways to help them remain part of one another’s lives. 

A sibling might: 

• Choose a favorite stuffed animal, movie or game to send to the hospital
• Make drawings or a collage for the hospital room
• Write letters
• Video chat
• Play a game together online
• Schedule a special call to say goodnight

When possible, families may also arrange one-on-one sibling visits at the hospital. 

Parents can share ordinary snapshots from the hospital — eating lunch, doing a craft or playing music — so siblings at home have a clearer picture of what their brother or sister’s day actually looks like. 

These small connections can make an unfamiliar hospital experience feel less mysterious while reminding siblings that they are still part of the family’s day-to-day life. 

Make sure they know they haven't become the “forgotten child” 

Supporting a sibling doesn’t always require a big gesture. In fact, consistency may matter more. 

“Siblings need to know that they haven’t become the ‘forgotten child,’” Speak says. “Their lives, feelings, questions, accomplishments and milestones still matter.” 

That might mean asking about their day, showing up for an activity when possible, celebrating something they’re proud of or making room for fun that has absolutely nothing to do with cancer.” 

“They don’t need everything to feel normal,” Speak says. “They just need to know that they are still seen, still heard and still important.” 

Let your community support the sibling, too 

Grandparents, relatives, family friends, teachers, coaches and other trusted adults can play an important role in maintaining a child’s sense of connection and normalcy. 

Keep inviting siblings to activities and social events rather than assuming their family circumstances mean they can’t participate. Offer practical help that allows them to continue doing the things they enjoy. And check in without pressuring them to talk about cancer. 

Simple questions such as “How have things been going for you?” or “Would you like some company?” can leave the door open. Avoid placing expectations on a child to “be strong” or reminding them that their sick sibling “needs them.” Siblings are allowed to feel sad, worried, angry, jealous — and also happy, silly or completely uninterested in talking about cancer that day. 

Support is especially important after the initial urgency surrounding a diagnosis has passed. Treatment may involve hospitalizations, milestones, changes in routines or transitions back home, and siblings’ needs can change along the way. Continuing to remember their important events, interests and relationships can make a meaningful difference over time. 

Know when to ask for more help 

Changes in mood or behavior can be a normal response to having a sibling with cancer. But if those changes are significant, persistent or begin interfering with everyday life, additional support may be helpful. 

Parents and caregivers should pay attention to ongoing sadness or anxiety, increased anger or irritability, withdrawal from friends or activities, difficulty functioning at school, significant changes in sleep or appetite, frequent unexplained physical complaints, or persistent feelings of guilt or responsibility for a sibling’s illness. Statements suggesting hopelessness, feeling like a burden or not wanting to be here should also be taken seriously. 

A child’s medical team, school counselor or mental health professional can help families determine what additional support may be appropriate. 

Certified child life specialists can also help siblings understand a diagnosis and treatment in developmentally appropriate language, answer questions, correct misconceptions and find ways to express difficult emotions. They can work with the whole family to support communication and coping throughout treatment. 

Above all, parents don’t have to navigate every conversation perfectly. 

“It’s okay to say, ‘I don’t know,’ ‘I’m scared, too,’ or ‘We’ll figure this out together,’” Speak says. “Children don’t need their parents to have every answer or to hide every difficult emotion. Kids need honesty, reassurance and the space to see that their parents are human also.” 

Learn more about the Center for Cancer & Blood Disorders at Lurie Children's