My best friend is a "grumpy old man", becoming grumpier, and I don't know what to do

I'm a cis female about two decades younger than him. He is my one true friend; the light of my life who's been with me through thin and thick, and we've had many adventures together. His voice on the phone renews me with life in this insurmountably difficult and isolated time of my life. Spending time together is life-giving... or it used to be. I find myself being too stressed by his moods to enjoy our time, and I don't know what to do, because i don't want to lose his friendship. He's always huffing and puffing, angry about something. Which tends to result in a tangent about evil liberals, or making fun of the Me Too movement (which hurts me, as a sexual assault survivor), hating on feminism, or hating on millenials in general (I am one), or hating on th BLM movement, hating the homeless, or any of the other Conservative views he follows (which I can't stand to listen to). He drives like a maniac and usually is cursing at the other drivers, honking like crazy. He hates everything about this city but can't afford to move. He only starts to smile and relax when we go on short trips out to nature, which don't happen often.

A concrete example of how bad it's gotten: he destroyed a wall of his house by punching into it several times, because his neighbor's tiny poodle jumps from her bed onto the floor every early morning, waking up my friend and disrupting his sleep. Instead of talking to her, he hopes she'll figure out what that punching noise following the dog's jumping down is.

I read that men become grumpy in their golden years due to dropping testosterone. Is there maybe hormone replacement therapy for men, the way there is for women? He is the grumpiest person I've ever met.

I suggested he find ways to relax, like regular massage therapy, but he's stubborn like a bull. He's not into psychiatry, so drugs are out of the question.

I'm sure his life is also very hard, but I can't help him too much, because I'm just now starting to learn how to function (PTSD from aforementioned sexual assault).

I don't know what to do. Help.

edit: to the POS who sent me a Reddit Cares message - eat dirt. Or hopefully get therapy.