--which I know (especially with your son) has been quite trying for a while now.

I can't add much to what the others have said--there's some really good advice in there--except perhaps to point out that if depression is anger turned inward, find an appropriate situation where you can turn that anger out. (That landlord might be a good place to start.)

Now, one must always be cautious of misdirected enmity--but I'm sure there are numerous places where that energy can be properly directed.

Bay at the moon.
Bang a gong.
Whack a mole.
Whatever gives some release.

This may not help more than temporarily, but it has mood-altering properties if done over time, even infrequently . . .

My relatives are not known for pithy statement nor cogent aphorism, but Great Aunt Jenny used to tell us to strive to be people that gave ulcers, not people that got them. May be something to that.