When someone does something bad to you why do they try to avoid you?

Either he's your ex and that means you're no longer together ... making this (and your other post) moot and pointless. Or he's still your partner (but with a marginal separation period).

If he's your ex? He's not obliged to apologize. Is that possibly bad karma? Maybe. But by being your ex? He's no longer part of your social circle. You need to clarify this very important detail (not necessarily with us... at this forum) but with yourself.

Whether he remains in contact with your mother? That's irrelevant. They're both adults. They can still consent to choose to communicate with each other.

Given the details of the prior thread you wrote? He sounds toxic and a possible danger to you and your family (at least at an emotional level if not further into something physical). Keep him as an ex. Let your family know that fact. Let them choose to remain in contact with him or not. That being said, that there are emotional consequences to that decision they will have if they choose to do so.

FYI: Please don't make any new threads on the same subject while ignoring the advice posted to your previous thread on the same topic. That's just bad forum etiquette.