I raised three boys. I'd say there is EVERY chance the child sat back there quietly for the ride to daycare. After he buckled him in, it's quite believable he never saw him, either.
I wonder if people who think kids babble all the time had been parents of little girls? They do seem more verbal - although this sweetie could speak clearly it's not clear he talked non-stop.
Here's the deal. When i look at a case where someone is claiming innocence, and think, "is that possible, what he is saying?"
In this case, yes to everything.
"Is it possible the child, after being strapped in to the carseat sat quietly for the few minutes it took to get to work"? yes
"Is it possible the dad didn't have a clear visual on the child both getting out of his car, putting something in the seat at noon, and then getting into the car at 4?" yes
"Is it possible that both parents had discussed their fear of hot cars and each had googled for more information, sensing they were at risk?" yes
"Is it possible daycare never reached him that day?" yes (this will turn out to be a verified fact, either daycare reached him or didn't
"Is it possible that he forgot the baby was in the car after strapping him in?" yes. Otherwise, it wouldn't be common. What is uncommon is for the forgetting to last so long the child passes away
In other cases, I start the same way. Is what the accused is saying possible in each case? In the case of Danielle Van Dam, I hit the wall with "is it possible the accused coincidentally drove all the way out to that remote spot exactly where her remains were found out in a jungly mess, states away from where she went missing, where he got stuck and had to have his car pulled out by a wrecker". No. No that's not possible it's a coincidence.
That's what I want to see in this case. Something that's not possible.