Quite possible. Just hard to say. Another theory I’ve seen vindicates him entirely...that there was a fire and he diverted to try and reach a nearby airport, but then was overcome by smoke and fumes, cue Payne Stewart scenario. Sim flights to nearby landings could easily mean he felt there was something wrong with the plane but they wouldn’t listen or couldn’t find anything.
It’s entirely possible someone onboard had an attack of SJS, but at the same time we have to consider it’s also possible everyone is innocent and this simply is a bizarre tragedy rather than a conspiracy.
I can’t get past the “fact” (ha!) that the initial course deviation was loaded before takeoff. If true (!) that indicates intention.