Few things to note here:
It's pretty obvious, for most of us who know autism, that Jett Travolta was autistic. Whether his parents were dealing with that or not, I have no idea. I won't slam them for not confronting his autism when none of us really know if they did or they didn't. We can guess that they didn't because they were Scientologists-but we don't know.
There's no evidence that Jett was going through Scientology detox. What Preston said is that her son was on a "detox diet". I'm not sure what that entails, but, looking at photos of the boy, he did have a weight problem. So, it's not unlikely that the "detox diet" was just that: a diet.
It's possible that Scientology played a role in the boy's death. It's equally possible that his death was an accident. In any case, whatever they may have done wrong as parents, Preston and Travolta are paying the ultimate price now, and I'm sad for them.
I say, wait and see what the autopsy reveals before speculating. Cause right now, everyone is like a talking head. There just isn't enough info available yet to be able to form the whole picture.