Since I didn't know DJ AM personally, I only met him twice, once at Coachella and the other at a Ed Banger Records label. He seemed to be a pretty nice guy, but we all put on a mask from our personal problems.
The reason why I am defending him in the first place is that I used to have a stimulant problem and had various friend's and family that died from various drug OD's. To say that he had it all, doesn't really mean much. Growing up in Malibu, I had the notion those that had who money were happy. Yes, I did meet a lot of people who were happy, but I also met a countless number of people who got that happiness from using drugs (coke/benzos for the most part).
After high school, the reality of college and being independent caved in for a lot of my close friends, soon they were abusing drugs more and were in and out of rehab. But that's not my main point, because who I feel really sorry for most are people who can't control their drug addiction, whether it be someone who is rich or in poverty.
In the case of DJ AM, I never knew he even had a drug problem in the past but the reality of drug addiction is that if you go sober there is always the chance of relapse and my only speculation is that he either did just that or maybe something else?