"Where was his support, via family and friends. It says he was a prolific users and recently gave it up."
If you'd ever been close to an addict you'd reluctantly come to understand that your support or otherwise means nothing to them. It's all about them and their craving for the drug.
It's why organisations like "Alanon" exist, i.e. to help family members learn to live independently even when still in a relationship with an addict. They will suck you dry, blame you for their problems, and take you down with them.
If he recently returned to heroin after being off it for some time, that would explain the overdose. Presumably he based the dose on his previous level of tolerance which would now be diminished. Result: the end.
