Ironically, they'll probably call the cops on you.
Take it from me, Professor, the very last people that these particular idiots will be calling are the police.
(Considering that every one of them has, at some stage or another, done time in various prisons, their attitude towards representatives of the Law are, to say the least, somewhat hostile).
Also, the bloke in question, is very much aware of the utter contempt that I have with regard to his partner. I was the one who stood by him and took his side on the last occasion that she physically assaulted him. But, as is sadly so common in cases of domestic abuse, he later made excuses for her behaviour and chose to take her back into his life. I made it absolutely and abundantly clear to him that I never wished to be in her company again or have anything to do with her whatsoever. And I have, and will continue to keep to that vow.
As I learned from my own bitter experiences of a couple of former partners- albeit in my case, they were of verbal and emotional abuse and controlling behaviour - there are certain people like her that are utterly incapable of change for the better.
At the end of the day, he is so terrified of being alone and accepting the fact that, between his advanced age, economic circumstances and his own personal issues, this is likely to be his lot-in-life going forward, he will forgive her many horrible personal flaws. And the worst of it all is that she herself was apparently the victim of childhood abuse. Which in my view, makes what she has done even more unforgiveable.
And I speak as someone with experience in that area myself. In my case, that abuse manifested itself in the physical fashion. If you have been through that kind of horror or anything like it - as I have - then it is surely incumbent on you to do all that you can, to avoid perpetuating that kind of repulsive behaviour upon anyone else. At least that is the way that I choose to so from a moral point of view.
In any event, he has made his bed and can lie in it. Any sympathy I might have had for him has long since evaporated.