I haven't read every post so apologies if I am off the mark or repeating someone but here are my 2 pennies worth.
Tackle it like he would. Dont ask for his help. Try not to moan or lecture him and dont get emotional. Tell him what's happening. It's what he does. Play his parenting avoidance games.
Fake a crisis where you have to leave in a hurry at the weekend and pass your DS to him 'Oh gosh, my friend Jo has been in an accident and needs me to sort out her 6 kids.' Then jump in your car and go to a spa. Ideally empty the fridge before you go, put all your childs clothes in the laundry and hide the nappies.
Think of imaginative reasons to be out which he can not argue with. 8 weeks of physio for your back, damaged by a year of carting a child around? And they finally have a slot for you at the weekend!
When you are out, turn your phone off and do not thank him when you return. if he moans, look genuinely confused, 'dont you want to be with your son? Why didnt you just go to the shops?' Etc. Also, when returning do not rush to take the baby off him. 'I need a long shower after looking after those 6 tears aways. Could you get dinner ready?'
One last tip, be a bit less good at parenting. 'I cant be bothered with the whole bath bedtime routine. Shall we just keep him up? Well if you want to put him to bed that's fine. I'm watching this.'
His behaviour needs addressing but first I think you should try to turn the tables. For your own amusement if nothing else. If you could recreate a situation hes put you in , that would be even better.