There is always a point where you have to say "no I can't work with this person any more", but while you are still trying to it's worth trying to figure out why someone is behaving as they do.
Agree, plus I’d add: if we are going to criticise other people’s communication style/abilities or attitude, then using a vague, vulgar and hurtful slang term like “arsehole”/“asshole” (and similar slang such as “dick”, “prick”, etc) is an example of exhibiting the very thing one is complaining about in making the complaint, which is fundamentally hypocritical. One can state the same concerns in a more professional way, focusing on the details of the specific behaviour pattern not a vague term which can refer to lots of distinct behaviours (e.g. people with ASD traits who hurt the feelings of others because they honestly have trouble thinking about them, versus people with antisocial or narcissistic personality disorder traits who knowingly hurt the feelings of others because they enjoy doing so) - labelling the behaviour pattern not the person, acknowledging that it is entirely possibly due to an unintentional skills gap, (sub)culture clash, differences in life experiences, neurodiversity/neurodivergence/mental health/trauma, etc.
I also think it is helpful when criticising the flaws of others to try to relate them to one’s own, whenever possible - e.g. sometimes in the past I did X and from my perspective it looks like you are doing something similar-hurtful labels are not encouraging that kind of self-reflectiveness at all, they promote the idea that “I’m one of the good ones but you are one of the bad ones”
Comparatively, I find subtweeting him from the sanctity of Mastodon, with a few insults and backhanded complements thrown in for good measure, a bit low.