ExH has a history of depression and alcohol abuse. Currently has the DC (12 & 9) EOW and a night during the week. DD12 has a phone on condition that I know the password, and can check it on demand (she's autistic, often trusts people too quickly, and I worry about her safety online). From checking her phone, I can see that she's often gaming until midnight when she's at her dad's; when she's with me, her phone goes off at 9pm and we've not had any problems with that. ExH allows unlimited access to gaming for both DC; both have their own computers in their bedrooms at his, and DS9 frequently eats meals in his room while gaming. DS says at the weekends, he wakes his dad up at about 8am, his dad gets him breakfast and then goes back to bed, and DS wakes him up if he needs anything. This weekend, ExFIL was trying to get hold of ExH and couldn't; there are messages on DD's phone from ExFIL and ExH's girlfriend asking her to go and wake up ExH because they were worried as they couldn't get in touch with him - this was at 12.15pm FFS 
I've told ExH about the late night gaming at his, and he said he'd tackle it, but nothing's changed. I've expressed my concerns to him repeatedly, but nothing's changed. He's very skilled at appearing to put the DC first - he's even the Safeguarding Governor at DS' school - but behind closed doors it seems that he can't be arsed
He's impossible to motivate - divorce took me four years because he simply wouldn't engage with the process - and now I'm wondering what the hell I can actually do to make sure things change. The DC adore him, but even they say he doesn't make them do anything they don't want to, so they often stay in their pyjamas all weekend and don't wash or leave the house. This is shit, isn't it? What do I do now?