Agree with @category12. Block the social media.
From my perspective as a child growing up- my mum divorced my alcoholic gambler father. We (me and my twin brother) carried on visiting him maybe... for a weekend a month? Then school holidays only. And even then he couldn't keep straight. I liked my dad. I never noticed he was drunk or tipsy. He was a happy drunk and great with watching kids telly with us, playing, drawing, farting games.. But. He was neglecting us all the same - I used to hear hushed conversations from other family members on how we had only been fed sweets all weekend. Or how I went to school with hair in a state that teacher had to step in and tie it up in a pony. I didn't care, from child's point of view, he was great. But the drinking escalated. A few times my paternal grandparents "rescued" us from his drunken presence and took us to their house instead.
At some point he stopped turning up for our birthday parties (he knew he would be asked to leave if he turned up drunk. So he chose to.. Drink. ) And then he stopped turning up at all. My brother and I were 7 or maybe 8 years old. We never saw him again. Just shows the power of addiction. His dad, our grandfather, assumed that father figure role and was over compensating almost by being the most loving, sensitive, generous grandpa in the world. He was lovely.
Our dad was never mentioned. Mum had 1 or 2 talks with us explaining what divorce is and that not all relationships work out. Said dad has a mental health problem that makes him drink so it's better if he's not around. But no badmouthing, no drama, barely any mention at all. And you know what? We coped. Actually did very well. Got on with our childhood.
As I got older I hoped he would never surface because that would need thought, drama, emotion.. He wouldn't deserve that.
I found out he had died a year after his factual death. I was thinking - I found out my dad died today. And I feel nothing...
Cracked on with my day.
The moral of the story (other than sharing a personal perspective) is that if he is a "bad egg" and allows you and the kids to have some distance, take it. It is not necessarily bad and hugely traumatic for the kids.
To this day I'm grateful to my mum for allowing me not to spend my teenage years in a flat with an alcoholic and I'm grateful to her for not letting any of the stress and anger (I bet there was quite some! ) to reach us kids.
Stay strong, you and your little ones 