Re: day 7
IMO he is using your son to get to you. If your son is staying with him. Its like the Trojan House, once the giant wooden horse was brought inside the walls of their enemy, the Trojans came out of the horse and won the battle.
In that respect, I think he would ask you can he bring your son over to you place, or can you come spend time with your son while he will be around. And there is always the case of him wanting the 3 of you to go on a drive, picknick, park, outing etc... you get the picture.
I think the main thing is getting back in by using your son as the first point of contact. Don't fall for it. Get a friend to pick up your son when you want to see him or if you pick your son up, make sure that he is not around.
If your son is staying with you, it would be the same difference. Him saying "I want to come see my son" when he is just using the Trojan Horse. Just getting someone to drop your son off to him would help matters.