If he fell asleep with his foot over the accelerator and then woke up as the car left the road, this should be expected.
My brother did the same thing while my parents were following him home and had to watch him drive up an embankment and do a half donut before he was aware enough to hit the brakes.
They thought he was having a stroke or something, but he dozed for a second and woke up to a road sign directly in front of him and thought he was hitting the brakes.
If he fell asleep with his foot over the accelerator and then woke up as the car left the road, this should be expected.
My brother did the same thing while my parents were following him home and had to watch him drive up an embankment and do a half donut before he was aware enough to hit the brakes.
They thought he was having a stroke or something, but he dozed for a second and woke up to a road sign directly in front of him and thought he was hitting the brakes.