Yes, I think everyone would have to admit a child falling asleep essentially immediately, is possible. Possible and plausible are two different things. Convincing a a jury that it's plausible in THIS scenario, on that day, under all those circumstances...will be very hard. (Honestly, I'd be shocked if it worked. IMO.)
JMO
Maybe. Or probably, even, but who knows how this hopefully genuinely impartial jury will sort and sift and accept or reject evidence.
Relating to the discussion here about whether or not it would be wise for the defense to present the possibility -- not as a fact-- that Cooper might have fallen asleep.
I think the distinction is being lost as to why the defense would go there, if they do. They've already signalled the approach they'll take to explaining how it is that RH could "forget" he needed to make a turn at the intersection. That approach and explanation apparently will be scientific & medical and on it's face, is unrelated to whether or not Cooper fell asleep by the time RH reached the intersection.
IMO the defense is likely to present the possibility of Cooper falling asleep to address the separate question of how it was that RH, AFTER he drove past the intersection thinking Cooper was at daycare , could not have known Cooper was in the car.
Sleep or not sleep is not about the initial forgetting or not processing or whatever, but afterwards, the minutes more before reaching work. What is more likely? That Cooper was awake and talking or at least moving around in his car seat, and therefore making his presence known, even to a father who doesn't think he's in the back seat, or, a Cooper who is drowsy enough to be quiet enough for RH not to know he was there and asleep by the time RH pulled in and parked?
I can't imagine anyone thinking an awake Cooper explains RH's ignorance of him better than an asleep Cooper. It just doesn't. And, if one doesn't assume RH's guilt of malice murder, there is no other plausible scenario I can imagine for RH remaining clueless OTHER than that of Cooper drowsy, then asleep.