How will cancer affect my brother or sister?

Main Banner

What they might be feeling

On top of dealing with the physical effects of the cancer and treatment side effects,  your brother or sister will be going through lots of difficult emotions, and worried about practical issues.

It’s hard to imagine what your brother or sister might be thinking and feeling about having cancer... but probably many of the same things you are.

  • They may be scared.

  • They may be angry.

  • They may be very lonely.

  • They may be shocked or in disbelief.

  • They may be thinking about all the things they are missing out on. Or thinking of all the things they need to get done.

  • They’ll no doubt wish this wasn’t happening to them.

  • They may not like all the focus and attention on them.

  • They may worry about your family and how you are coping.

  • They may want to reflect on what’s happened to them in the past – the good things and the not so good things. They may want to think about the ‘meaning’ of their life and the ways they have contributed.

  • They may want to know what death will be like and worried that there will be pain.

  • They may be wondering about their beliefs and spirituality and thinking about things like what (if anything) happens after they die.

  • They may not want to talk or think about any of this stuff at all.

The best way to understand what your sibling is feeling is to spend time together. Even if you don’t say anything at all, your willingness to just be there and share this time will let them know that they are not going through this alone.

What can I do to support my brother or sister through cancer?

There are some really simple things you can do that may help:

Be positive

This can be good for you and your family, but don’t feel like you have to be upbeat all the time, especially if that is not how you feel. Looking for the positive in things can make a difference.

Be patient

Everyone in your family will be under a lot of stress. Routines may have changed and people may not behave in ways that you are used to. Try and understand that and be patient with them and yourself. If you find it is getting too much, take a walk, listen to some music or try other coping strategies.

Hang out with them

Just hanging out with your brother or sister can really help. You could watch TV together, read to them or find something to laugh about. Where possible see if you can still do some of the things that you did before they got sick – like annoy them and fight with them.

Help care for them

Being involved in caring for your brother or sister might be important for you. Let your mum or dad know that you want to help and find ways that you can do this. It may be as simple as holding their hand while they are having a procedure done or if they are much younger maybe feeding and bathing them.

Help them stay connected with friends

Spending long periods of time in hospital and stuck at home may mean your brother or sister loses contact with friends. They may appreciate being kept in the loop on gossip and other stuff that is going on. Little things, like helping update their Facebook page or sending out group texts can mean a lot to them.

Help them stay strong

Your brother or sister is likely to become sick and tired while undergoing their treatment and will not be able to cope with much other than trying to fight the cancer. Staying as healthy (physically and mentally) as possible will help their body recover and help them cope with side effects.

You can help them to eat well and keep their energy up by preparing good meals and snacks (including food they can take to the hospital). Read our tips for cooking for yourself and your family including advice about cooking for someone with cancer.

When your brother or sister is being treated for cancer they can get infections more easily. An infection could make them sicker, so they may need to stay away from crowded places or people who have an illness that they could catch. Wash your hands regularly to avoid spreading germs, and stay away from your brother or sister if you get sick.

What's going to happen to my brother or sister?


There are over 100 different types of cancer and each type is treated differently. The type of treatment your brother or sister will have, and how long for, depends on what cancer they have, where it is in the body and whether it has spread, as well as their age and general health. Learn more about cancer treatments.

It’s important not to compare your brother’s or sister’s experience with another patient – every one is different and reacts differently, even if they are getting the same treatment. 

One of the hardest parts is waiting to see if the cancer treatment is working. The doctors may try one treatment or combination of treatments, and then try something new. Treatment can last for several months or even years.

Side effects

Cancer is a disease. And most of the treatments for it make people feel and look much sicker before they (hopefully) start to get better. As well as trying to getting rid of the cancer, many cancer treatments have unintended effects on the patient called ‘side effects’. Unfortunately, many of these can be very uncomfortable and hard to deal with. They can affect how your brother or sister may look, feel or act.

Some of the most common ones are hair loss, weight loss or gain, vomiting and nausea, constipation or diarrhoea, sore mouth and swallowing problems, tiredness, poor concentration and memory (‘chemo brain’) and moodiness. Find out more about common side effects. Unfortunately, what side effects your brother or sister gets or how severe they are has nothing to do with whether the treatment is working. They can be pretty minor, or they can be severe and have a big impact on how your brother or sister copes with the treatment physically and emotionally.

Is he/she going to die?

There are many factors that affect the likely outcome for your brother or sister (their ‘prognosis’) including what type of cancer they have, where it is, how advanced it is and how they respond to the treatment.

Coping with not knowing

Even with all the best information sources and expert health professionals involved, sometimes there just aren’t answers for everything.

It can be really stressful not knowing what’s going to happen. Remember that even though you don’t have cancer, your brother’s or sister’s cancer will affect you and other members of your family. Learn more about how their cancer might affect you.

Collapsible field
You're not alone
Chat with people who get you. Get time out at our fun events. Talk to a counsellor (it’s free!).