I (46m) suffer from cptsd. I frequently freeze, fawn, isolate, etc. in response to stressors/triggers.

I have few friends or social support. Which is super bad. And of the people I do call friends, they often come with some less than desirable personality traits. But because my lonelyness is leaky, I try to navigate that best I can. Making compromises is better than spending years in isolation… right?

Anyways, my only local friend recently triggered me pretty bad. We had a disagreement about a contentious political topic. And one of his personality traits I absolutely hate came out. Seeing as our opinions are hardened on a topic, and I am willing to just put it aside as here is where we agree to disagree, he starts to come after me with judgement, categorizing into good/bad people groups, accusations, shaming, ultimatums, interrogation of moral character, etc. It is like from one moment to the next, if something ticks him off enough, he flips on you and justifies to himself any vile type of interaction as him being on the moral high ground lording it over the bigotted masses that have conspired against him and he must vanguish his foes…

He isnt a bad person (just a difficult one, as am I), and maybe my opinions where bigotted, but I cannot deal with this kind of judgement/devaluation/bullying.

Following in the wake of this interaction, I tailspun into complete isolation, freeze and a major depressive episode. I know I need to fix that, but I cant snap my fingers and declare it fixed. And it is very damaging to me and my mental/physical health.

I dont think I can change my friend. This way of reacting is something he does sometimes. I dont wanna lose him. But I also cannot afford to expose myself to be emotionally close to a person who full on triggers me and harms me because a bug crawled up their arse and they believe it is more important they score some points than what their behavior does to me. I know my triggers are my responsibility, so here is my question:

What can I reasonably ask my friend to do not to trigger me like that? I dont want him not to be able to express his opinion or walk around me on eggshells…