Whilst it is good to consider the feelings of others, one shouldn't always put others first, even if one does it most of the time. I have a relative who NEVER does anything for herself at all, which is silly, imo.
I don't know her of course, but it sounds like your relative is just being herself. For many people, serving others fulfills their own desires. Just as you would not want to give up your sense of self, for them to place their feelings ahead of others would be giving up their sense of self. We're all different.