This is a very difficult question, because it involves, in my mind, having to read your friend’s words and body language to see what sort of support she needs. I do not believe that there is a single answer that would be right in every case. It would depend on your friend, on what kind of person she is and on what sort of things she is likely to need to hear. Let us look at four possible things to say to her.
On the one hand, you could try to cheer her up or give her some hope. Your friend might be at a stage where she wants to believe that her mom will live. You could tell her that just because her mother has such an advanced stage of cancer does not mean that her mother will die soon. Some cancers are more lethal than others, but there is at least hope for patients in Stage III of most kinds of cancer. You could tell your friend that there are always some people who manage to survive and encourage her to think that her mom could be one of those.
Alternatively, you could try to talk to her about what will happen after her mother is dead. Perhaps she is a person who wants to face up to the facts and start thinking about what comes next. If you think she is like that, you could emphasize how she will still have a good life after her mother is dead. You could point out that she will still have other family and that she will still have friends. You can talk about how it will make her mother happy to know that she will be able to continue to live and thrive after her mother has died. This might help make her feel like her mother’s death will not be the end of the world.
If your friend is religious, you can talk to her (particularly if you are religious too) about God and faith and her situation. You can talk to her about how God must have a reason for allowing her mother to have cancer. You can encourage her to have faith that her mother will be with God after she dies and that her mother will want her to be happy about that. You can pray with her to help her feel better about her situation.
Finally, it may be that the best thing to do is simply to let your friend talk. Maybe she doesn’t need you to tell her things. Instead, maybe she needs you to listen while she lets her feelings out. In that situation, you should just listen and be sympathetic and supportive. Perhaps the things that she says will then tell you what you should say to her.
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