Father to out 4 year old son disrespects me to him , he even said to our son about himself that he's dying when he isn't which confused our boy. What do I do

My ex hasn't ever met our son, we live in different countries and although me and my ex are still legally married we are separated to be divorced and have been for 5 years.

I left my ex because of his emotional abuse. I tried to build bridges with him to call and see our son etc.

This is bulletpoint examples of the stuff he does and the disrespect he has ( some photos included).

Also just to add. He never pays child support.

- my ex coughed and jokingly said "I'm dying " our son got confused and questioned it and my ex said " yes, I'm dying, I'm dying " ?dead serious) my son turned around concerned saying " mummy daddy said he's dying " I said no he isn't see he's fine. Then my ex told my son to ignore me and said " ignore her , I'm dying every day". My son got confused more so I told my ex to cut it out and he refused.

-during a video call our son asks my ex " daddy why don't you listen to mummy?"(I hadn't spoken to my ex at all during this phone call ) instead of my ex saying something like " because she's not said anything " he goes up close to the camera and says directly " that's because I don't care for anything your mummy ever has to say". I immediately put my foot down, told him it was childish and wrong to disrespect me infront of our kid. He just ignored me.

-he ignores anything I say our son needs

-told my son " hey go tell mummy to get that stick out or her arse" because I was once abit stressed out in the background while my son was calling his dad. My exes mum was also in the call and told my ex off saying he can't disrespect me like that.

-tried lying saying " mummy is trying to stop us talking to each other " because I told my ex if I ever hear him comment again that he's dying I will hang up to prevent our son getting upset.

-If I'm in a 3 way call with his family nd someone has asked me a question while I answer he says " shut up nobody cares" or " are you don't with your dull life story now ?" So I blank him nd continue speaking to the other family members.

-he jokes and implies he's not our sons dad ( which he 100% is his dad )

Those are the few of the things he says and does around him .

Also here is me confronting my ex about the dying comment and he told me to do one basically.