Such an intelligent man.  Not only is he intelligent, he's also very engaging.  He's had serious drug and alcohol problems since he was a teenager, however.  There have been periods of time when he's been gone for years with no one hearing from him.  He'll literally hit skid row, be living in homeless shelters, and then my in-laws would pay for a ticket for him to come back, help get him settled while he found a job, pay for apartments, etc.  He'll manage to do all right for a few months, or sometimes even a year or so, then he'll start drinking and/or drugging again and it will fall apart.  Thankfully, when my mother in law passed away a couple of years ago, he was living near them in one of his sober periods.  She actually had a few good months with him before she died.  Sadly, this wasn't the case when my sister in law died 15 years ago.  No one had heard from him for a couple of years and we had no idea where he was.  He called a year after she died.  He had the nerve to be angry because he wasn't told!

He has a daughter.  He left on one of his several year binges when she was about three.  Her mother decided to not allow him to have contact with this daughter when he drifted back every so often.  She always allowed contact with the rest of the family, so this was difficult, but understandable when he was home.  His daughter is now married with two young children and she will not talk to him.  Its just a very sad, tragic story all the way around.

Ofcourse, being that this man is in his late fifties now, mental illness is also a large part of his problem.  Its hard to say whether the mental illness led to all his addiction problems or whether the years of abuse led to the mental illness.