He's been with the airline for 30+ years, 18k+ hours, and dedicated his life to aviation. If there's anything stable in his life it would be that - and I seriously extremely doubt he would threaten it.
It might seem unlikely that one of the pilots would fly the plane for hours in the wrong direction. But it also seems incredible that the plane would turn itself around, kill all the radios and head for the great abyss on autopilot no matter what the failure mode. The theories advanced so far for an emergency divert followed by crew and pax incapacitation are no less convoluted than many hijack scenarios in my view.
The captain did have a couple of significant events in the days leading up to the flight with his wife and kids moving out and his political hero being sent back to prison for sodomy.
MH 370 in the Indian Ocean is kinda like that turtle on a fencepost. You know it didn't get there by itself.