Churn and Burn
Aside from any question of guilt, I was curious about what happened to the Apple stock price in 2015 till now, and I found this handy graph.
Looks like there was a general downturn for Apple late in 2015, sure enough. And the idea this guy panicked and dumped all his stock hangs together plausibly.
But less than two years later the stock was back up to its value when he sold out and thereafter climbed significantly, before dropping back to the sale value again. If he'd kept the stock it would be worth roughly the same as when he sold it, after large positive and negative swings, and the earnings toward the end would have been significant too.
If he did do this deed, he's stupid. The fact that his job is to prevent people from engaging in insider trading from within Apple, just makes it that much more stupifying.