Father's amirite

Hi hi! 
So, some context. My parents have been divorced since I was pretty young, and I've been living at both their places until like end last year/early this year. After a lot of arguments with my dad I had decided that I was done, and to just live with my mom. The thing is that he keeps trying to push himself into our lives.

My parents are still in contact with each other, so they often catch up on how I'm doing. That's fine; except he can get pretty upset when there's things that my mom does know, but he does not. Some examples are when I got my septum piercing, or when I legally got my name changed (FtM). He keeps getting mad at her for not telling him things about me, even though it is none of his business, in my opinion. She feels as though she's a messenger between us, which she doesn't like, and that sucks for her. Because of that, she's asked several times, including today if I could just get back into contact with him. I've stated multiple times that I'm not interested, and I just don't know how to get him to leave us alone, especially without causing a huge argument again. It's not too much of a bother for me, so I can keep going this way and just hope he gives up, but I get that my mom's pretty tired of it.

Just wanted to get this situation off my chest.
🙏Bless🙏