Well I read it all, glad the party went well. Sorry about your brother and family.
Also it was good that you and H did sit down together to talk to son-even if H didn,t participate as much as you would have liked.
I am not surprised son said he felt like he is being punished after all he has been up to he should feel that in away(jmo) He obviously feels he can treat you anyway he wants and you will put up with it all.
However I think your son will also manipulate you big time A and lay a huge guilt trip on you. Do not let him. He is a child and clearly does not see that you only have his best interests at heart.
Your son knows you love him A,but you do need a break from his complete lack of respect for you and family rules. I hope his Dad can help him find that respect for you and improve his school attendance and curb his habit of going awol whenever he chooses.
I think for now you just have to give H the benefit of the doubt and just wait and see.
Worry about H's financial motives IF and When it happens for now your sons behaviour needs to be sorted. Your son is on a slipery slope and just maybe your H can do some good. You will not lose him a few weeks away is not going to undo the 15yrs you raised him.
Take care.