He is currently staying at his sisters (supposedly) where she is paying him money to babysit.
This is disturbing, a drug addict babysitting? Does she know he’s a drug addict and recently relapsed?
I agree, you and your husband are willingly giving all the control and power to this manipulating drug addict. Like you are both looking towards the most damaged person in your lives for all of YOUR answers for YOUR happiness.
I get you wanting to work on your marriage but it always appears that all your husband wants to do is work on his son’s addiction and without any outside help to boot. The marriage is coming in second all the time.