That's irrelevant. There are always going to be things going on in people's lives. I can tell you for certain that nothing else significant changed in his life during that timeframe other that smoking pot. We were the type of friends that spend all of our free time together.
I'm seeing a lot of attempts to deflect any blame from pot. I find it quite interesting. I've had one person call him a liar, others claiming it must be some other cause. And now you searching for something else.
Here's the thing... there are always multiple factors that affect people's behavior. In that sense, the word 'cause' becomes the excuse for others to deflect because it certainly can't be proven philosophically, and certainly there are a list of contributors. But there is a level of common sense that can be applied and it is clear that smoking pot is, if it makes you feel better, a primary contributor.
I could claim that when a drunk driver kills a family, we should not blame the role of alcohol, that there must have been some reason he drank so much and acted so irresponsibly. But that would be avoiding the real point, and the fact that alcohol was a primary contributor.
So please, everyone, stop looking for excuses for pot. Its OK to use common sense and admit that a mind affecting substance can have a negative impact on people's lives. There is ample evidence, I've seen if first hand. It doesn't mean its an evil substance, or that you are wrong for using it. Denial and scapegoating is your own problem, not mine or my friends.