Hopefully, your husband will get the help he needs to manage his depression. There are so many things he can do to live better than his mother. What I like my husband to know when I'm depressed is that:
1. pushing me doesn't work
2. counseling is very important
3. taking needed medication is sometimes absolutely neccessary
4. keeping in a routine is very important, I don't do well with spur of the moment stuff
5. I need help with keeping my life organized and calm
6. a hug is better than any words can be
7. patience is a virtue
8. let me have space when I need to be a lone

I'm sure there are plenty more but these are the most important to me. Your being here looking for help is a very supportive thing to do. It shows you are really interested in finding answers. I wish my husband would do more research, because I think it would help us both.

Good luck to both of you.