I'm so sorry that you and your husband (and his mother) are going through this. The hurt that we feel with depression does eventually turn into anger, usually the anger is directed inward but sometimes it is directed to the people we care the most for. Although you may not want to hear this, if he has been truly dx'd with depression and now his anger is directing outward instead of inward, it sounds like he is making progress. I know that it doesn't seem like it because it is at the expense of everyone important in his life however the most destructive and dangerous part of depression is when we hate ourselves. If he is not seeing a therapist yet, I would highly suggest that he sees one soon. He needs to learn how to deal with his anger and made realize that he is hurting a lot of people (although he may not realize it yet).
IBS, Diverticulosis, GERD, Disc Degeneration
"If you don't like something change it; if you can't change it, change the way you think about it" - Mary Engelbreit