I never saw your original post, but I just want to let you know you're dling the right thing.

My parents split when me and my brother were young and he was also always hours late (if he showed up at all some weekends). My mother never decided to go out and make us unavailable if he was a certain amount of time too late, and she talks now about desperately wishing she did. The distracting activities is a great idea!

My mother was big on "being the bigger person" to a fault. I'd be all packed up and ready for the weekend and sit on the steps for hours being excited and waiting for him, with my mum trying to tell me that he's probably just busy and will be here soon, no it's okay he still loves you and won't you please come inside and have a cocoa?

...It took about two months of this for me to just start planning all my sleepovers and seeing friends for "dads weekend" just so I could be happy on my weekends and at least maybe mum didn't have to drive me, and my little brother (I was 10, he was 6) started doing the same. I can without a doubt say that that experience was what caused me to believe that I couldn't rely on or trust in someone even if they were supposed to love me and my relationship with my father has only just begun repairing now, 14 years later because I care about his new kids and making sure they have someone to call family just in case he leaves them too.

You're showing the father that if he's late, he's missed his chance to see his son is a great way to make sure he realises that he should be making seeing him his first priority, and I'm so glad it's working! His father is still a mega asshole, and you need to have words to him about what he said, and how strongly your son seems to be taking it as his fault when it is 100% dads fault and he is a gigantic asshole for making his son feel bad about him being too late.

As for your son, talk to him about it not being his fault that daddy said some mean things, he was wrong, and that you both love him so so much. And look into a child psychologist for him if your can afford it (you can talk to the father and look towards splitting the cost if need be! or find one with a sliding scale) for his current issues because of what his father told him, and the issues of dealing with parents separating.