my boyfriend's mother has stage 4 cancer

well as you can see by the title... this is a pretty touchy topic. I'm a really caring person, but I just don't know how to help or be supportive in this situation. he'll bring it up every now and then but typically doesn't want to talk about it. he has a very fragile ego so he thinks that if he shares his feelings he will risk his manhood. I've told him repeatedly that I'm here to listen and just to be there for him. I'm just not sure how to take care of this and just be a supportive caring gf I really just want to help..