You're only one person, of course it's too much to be expected to be his only lifeline.
And it sounds evident that his homelife is playing biggest role in his emotion state of mind.
Living in an abusive home does bring about depression no doubt. How the ideation plays itself out comes in many variations. Of course he is angry and ideating up a storm.
How to help resources may be tucked away in domestic violence literature. ? The literature that discusses why victims stay stuck in the cycle. Maybe read there for some tips for you? In reference to how to be supportive?