Doubt it was bath salts. I learned back in my college days that if you smoke weed after you're drunk, the effect is like getting hit by a freight train. You're almost instantly incoherently trashed. This was 20 years ago. I haven't smoked weed in many, many years so I have no idea how potent the stuff is today, particularly in California where it is practically legal.
As someone who had a brother who drank heavily and smoked weed all the time, you are right. My brother also died at 47. 32 years abusing yourself will do that.