Without having read through this entire thread, the original post sounds like real bad news to me.
I have a 2nd cousin who married a minor league pitcher. Nicest guy you could imagine, the handful of times I've met him, and by all accounts was an upstanding and motivated guy. Had a nice minor league career (and mind you his wife was doing pretty OK in her job as well), kind of on the brink of breaking into the majors most of the time until he started breaking down with injuries later on. Had a series of surgeries as a result of said injuries and in the process of recovery apparently became addicted to pain killers. When that became "not enough," started selling the pills and using the proceeds to buy heroin. The situation had progressed to this point without his wife or her family knowing anything, until one day when he went to drop their two young daughters off at the mother in law's house, then passed out behind the wheel about 10 min later, slamming into a parked car and catching his on fire. Witnesses said it went up so quickly they never would have been able to get the kids out of their car seats. Really scary E36 M3.
Pretty much everything came unraveled from that point and everyone saw the blatant warning signs that were missed. Came to find out he was stealing from his wife's bank accounts and had put the family deep into debt, ect, ect. His wife and her family cut off all contact and to my knowledge its been that way to this day. Really sad story, but seems all too common these days.
Your family appears to be in denial. The warning signs are all there and they are choosing to ignore them. The situation will come to a head, one way or another, sooner or later. I really don't know what else to tell you, but I don't think this is something you can tackle without everyone's support.