You sound like you have an awful lot on your plate. The awful thing is that some children react very badly when parents are unhappy. Sounds like you ds is just doing this. Try not to blame him (hard I know). You all sound like you are having a difficult time at the moment.
I think you and dh have to sit down and have a chat about how you manage your ds. I would try to make it positive discipline rather than authoritarian style parenting if possible as some children just react even worse to over the top punishment type parenting.
Both you and dh have to be working together though. Think about some of your ds's worst behaviours and decide on some strategies for managing them. It may take a while but at least you will both feel as if you are doing something to help ds and to make your family life more peaceful.
As for all the other things they all sound very worrying but for your own (and your ds's) health of mind you need to detach a bit. The things you are worrying about sound like things you have little control over, so you need to let them go a bit.
Do what you can or want to for your birth mother and father but don't worry if it has no effect, you have no control over how they behave, they are adults and outside your control.