My mother told me that she has lost her will to live, that she sees no sense in it anymore. I know she would not kill herself, but she hasn't been taking care of her health for example, which is also a way of dying slowly. I don't want her to feel that way but don't know how to help. Do you have any suggestions?
I don't know your mother and I don't know the circumstances that have led her to despair. But here are some thoughts that could apply to anyone.
We all need a reason to live. We all need to feel needed. We all need to have a sense of purpose. Having a purpose is far more important than having money or a comfortable life. It is even more important than our health. A life that is healthy but purposeless is like a blunt pencil. It has no point.
Purpose comes from serving others. When we know that we are giving, that we are contributing to the world, that we can make other people happy and help make their lives better, then life is worth living because we feel we need to be here.
Perhaps your mother already does a lot for others. Make sure she knows about it, that she feels appreciated. And if she isn't currently doing anything purposeful with her life, then you need to find avenues for her to be productive. You might have to be a bit sneaky here. Think of something that she is able to do to serve others, and if that need doesn't yet exist, create it.
If she is good with kids, give her more responsibility to look after kids. If she can drive a car, find an organization that needs volunteer drivers. If she can paint, let her share her talent in a way that helps other people. It is not enough for her to just indulge in painting. Perhaps she can donate her work to charity.
Maybe she doesn't have any of those skills. But one thing she does have is time. And that she can give. Find people with more serious health problems than hers, find people who are even more lonely than she is. And let her give her time to just be with them. Then she will very quickly find a reason to live.