It sounds as though he's really spinning and in a bad spot.
I know it is especially difficult for you since there is the history of abuse, and the last thing you want to do is placate him or get yourself wrapped back into that dynamic.
However, it also sounds to me like he's really having an incredibly difficult time and has no idea how to handle it. Is there something at all you can do to help him, even while not engaging in his craziness? Something that you can be OK with, thinking about it less in terms of allowing him to treat you in a certain way or reinforcing his behaviors with your own seeming acceptance, and more about just reaching out a hand to help him when he's so clearly in crisis?
One thought I had-- what if you wrote him a note and slipped it to him? Said you know he's really upset and you'd like to talk with him about it but you're worried he'll get angry or yell and you simply can't do that with him any more. You might say you never meant to make him feel badly and are sorry that he's having such a rough time, and to please let you know if there is anything at all you can do to help him. Anything along those lines that is true from your standpoint but also lets him know you care about him and want to know how he's doing. Then you can walk away and let him read it without responding in the moment. Maybe that is a way to defuse the situation without giving him the opening to let out his frustrations on you?
Me (46) H (42) M:14 T:18, D9 & D11 4/19 - 12/19: series of escalating BDs 9/20 - present: R and piecing