by CanTeen07/12/2018

How to Talk to My Child About Their Sibling's Diagnosis

Telling your child their sister or brother has cancer can be difficult and overwhelming. But talking openly and honestly about cancer and what is going to happen to their sibling can reassure your child, prepare them for what’s next, and build their trust in you. 

How to talk to your child about their sibling’s diagnosis

  • Prepare yourself  
  • Decide when and where 
  • Decide who you want to be there with you 
  • Be open and honest 
  • Explain what will happen next  
  • Help them get more information and support 

Prepare yourself  

  • Make sure you are ready. Talking to your child about their sibling’s cancer can be confronting and difficult. Don’t attempt it while you’re still in shock or dealing with strong emotions. 
  • Talk through your concerns, and perhaps practice what you want to say, with another adult. You could ask the oncology social worker, psychologist or other health professional at the hospital for some advice on what to say, or call a CanTeen counsellor to talk it through: 1800 835 932. 
  • Get advice from other parents who’ve been through this in our online Parent Community. It can be a relief to know you’re not the first to grapple with this, and get advice about how they broke the ice with their child. 
  • Be prepared for how you think your child might react. Common reactions include sadness, fear, anxiety and shock or disbelief (they may seem to have not heard your or not react at all – which means they need some time to process it). Find out more about how to manage your child’s reaction to cancer. 
  • Be ready for questions. If you don’t have the answers, it’s okay to say you don’t know and that you’ll find out and tell them.  

 Decide when and where 

You are the expert on your child – knowing how they react (and how to calm them) when they are angry or upset, what makes them laugh – so you will know the best ways and times to talk to them. 

  • There is no ‘right time’ to tell your child about their sibling’s cancer, but generally if you delay too long they will have worked out something is wrong. Trying to keep it secret can be stressful, and your child will probably sense that something is wrong and wonder why you’re not telling them. 
  • Tell them as soon as you feel able. Even if you don’t have all the information yet tell them what you can, and that as soon as you know more you will tell them. 
  • Choose a time and place where there’s unlikely to be any interruptions or distractions. 
  • If you have more than one child it may be better to talk to each one separately. They may need to know different things because of their age or developmental stage, and they may be more willing to ask questions and more open about how they’re feeling if their siblings are not there too. 

 Decide who you want to be there with you 

  • In a two-parent household, it may be a good idea to talk to your child together. If your child who has cancer is an adolescent or young adult, they may want to tell their sibling or be with you when you do, discuss this with them first and decide together. 
  • If you’re a single parent, you might like to have an adult, relative or friend who has a strong relationship with your child, to be with you. 

Tell your child – openly and honestly 

  • Start with questions to check what they know about cancer.  
    Children have different ideas about what causes cancer and might have misperceptions (for example, that everyone who gets cancer will die, that you can catch cancer or that they caused the cancer). If they do know someone who’s had cancer, usually it’s an adult. For younger children, it can be confusing and frightening to learn that children can get cancer too. You might need to explain that just because Granddad died from cancer 10 years ago doesn’t mean their sister/brother will, because theirs is a different type and treatments have improved since then. 
  • Be honest and straightforward. Talk to younger children in a way that’s appropriate for their age but still use the correct terms. 
  • At this stage, the basic information they need is: 
  • the type and site of the cancer  
  • how it will be treated  
  • likely side effects of the treatment and how it will affect their sister or brother 
  • how the cancer is going to affect them and your family life. 
  • Don’t be afraid to express your feelings. This lets them know it’s okay to show your emotions, and that you don’t always know what to do or say. Reassure them that even though you are all upset and concerned, as a family you can handle this. 
  • Reassure them that most young people survive cancer. 
  • Make sure they know their brother’s or sister’s cancer has nothing to do with anything they did, said or thought. 

 Explain what will happen next  

  • After they’ve had time to process the news, explain what is going to happen to their brother/sister next and the changes that will affect them. For example, if your child is going to be in hospital and you will be spending a lot of time there, let them know who will take them to school or sport.  
  • Reassure them there will be a plan and that you will let them know about any changes. 
  • Don’t bombard them with too much information at once. They’re probably pretty overwhelmed right now, so give small amounts of information so they can process what is happening.  

 Help your child get more information and support 

  • Young people often cope with uncertainty by seeking more information. There is a LOT of information about cancer on the Internet and not all of it is sound. So point your child to reliable information that is written specifically for teenagers or children, such as CanTeen’s website and books (all available on the website): 
  • Let them know who you are going to tell and discuss who they can get support from.  
  • Encourage them to talk to you, other family members or friends about how they’re feeling, and ask if they would like to talk to a cancer counsellor. 
  • Remind them that while no one will have exactly the same experience as them, there are lots of other young people out there who have a brother or sister living with cancer. Encourage them to check out CanTeen’s online community where they can connect with other young people affected by cancer in their family and read their stories. They can also contact CanTeen counsellors online.  

 Reassure, and keep communication going 

  • Assure them they will always be looked after, and that while you may be focused on their brother/sister, you love them and will be making time to spend with them too. 
  • Keep them informed about what’s happening to their brother/sister, so they don’t feel left out. 
  • Give them time to digest the information and ask any questions or tell you how they’re feeling.  Tell them they can ask you questions anytime and if you don’t know the answer, you will find out.  


More advice/support 

It can be really helpful to talk to other parents who have or have had kids at a similar age to yours when they or their partner was diagnosed to find out how they handled this conversation. Join our Parent Community.  

Ask the oncology social worker, psychologist or other health professional in your child’s treatment team for advice, or call a CanTeen counsellor: 1800 835 932. 


Useful sites/resources 

For you: 

> Cancer Council’s booklet “Talking to kids about cancer”

> Macmillan Cancer Support booklet “Talking to children and teenagers when an adult has cancer” 

For your child: 

CanTeen’s website has a section with information for young people who have a brother or sister diagnosed with cancer: 

> You can also download or get a copy of CanTeen’s ebook Dealing with your brother’s or sister’s cancer 

> Camp Quality’s Kids’ Guide to Cancer app is for children aged 8-13 who have a parent, sibling, friend, or loved one with cancer and answers common questions about cancer and includes stories from other children affected by cancer.