boyfriend struggling with anger outbursts and dissociation

my boyfriend struggles with these random episodes of anger. he often has anger outbursts and gets mad and snaps at me... but within a few minutes he'll come out of it and be extremely apologetic and feels guilty and usually ends up self loathing. he's hurt me with some of the things he's said before and he knows it and feels really bad but he says he can't control himself when it's happening.

recently, for the second time this year, he had a dissociation happen along with it and it lasted a few hours. i texted him early in the morning because i woke up and couldn’t sleep and he got mad at me and told me to go to sleep otherwise i'd be tired all day and would ruin it. i woke up again later and he was acting normal again but i could tell by his texts he was still off, and later on he asked me if something was wrong because i was acting weird and i told him i was hurt because of what he had said to me earlier. he snaps at me again, we had a small fight, then says "i'm sorry for hurting you or whatever, happy now? just cheer up for f*cks sake" and i left him on read until he started asking me to stop ignoring him. i tried to explain myself and he started getting really upset again and asked to be left alone for a while.

a bit later he texts me again and told him that he reread the conversation and can't remember typing any of that, and he only just snapped back into reality and was hyperventilating. he said he had tunnel vision when it was all happening and felt like he was not in his body; an out of body experience. he said he didn't even remember who i was when it was all happening too. he was extremely sorry and ended up crying to me and told me if i wanted to leave him i just should but i promised him i wouldn't .

i too struggle with depersonalization disorder and he knows that but i have never snapped at him like he has to me, and i never have anger issues so i feel like we have a different problem. he had a very abusive childhood, physically and emotionally, and still struggles with trauma and abuse every day. i really want to know how i can help him because i'm worried it'll start affecting our relationship; i'm already really hurt by a lot of it and he feels guilty all the time. don't tell me to leave him because i'm not going to. i want to know how i can help him, or if there's any type of dissociative disorder i can research into to see if it fits him. he can't see a therapist because he still lives with his abusive parents and won't be moving out for another year or so. i'm so worried about him, i really need help please.