I do boat...very often. I can tell you that the size of the motor isnt the issue, like many accidents, its the driver.
1st off, he should have known the way his boat is going to react in most or all conditions. He has a shallow hull bass boat which isnt very stable in the calmest conditions. Its a fishing boat, NOT a speed boat and the biggest difference is HULL DESIGN!
2nd ANY boater that knows anything will THROTTLE back when going over someone elses wake. Just because it was another boat "changing the lake or sea conditions" doesnt make it any safer, whether its one wave or a series, the conditions under his boat changed and he should have throttled back before crossing the wake. There is a reason why the offshore racing boats have a "throttleman" and a driver -speed control.
3rd You dont cross a wake almost parallel to the wave of the wake, you broach the wave with the BOW of your boat. About a minute into the video you can see him wrestling to keep the boat under control and from swaying side to side in CALM waters. When he crossed the first side of the wake his hull became VERY unstable (side to side) and once the hull lost contact with the water, he was just along for the ride.