Here's the thing. If "shit happening" means you forget your child in the car for seven hours, then you shouldn't have been a parent. "Shit happening" is not an excuse. Saying "shit happening" isn't gonna bring this kid's life back. If in the midst of anything, you don't think "Oh I left my kid in the car", then you have a piece of shit brain, or you're a piece of shit person. Bottom line, this guy either intentionally murdered his kid, or he was a failure. "Shit happens" doesn't make this any less bad than it is.
So lemme look at it from this guy's perspective.
Okay I'll just Google what temperature it takes to kill an infant.
I'll have my wife do the same.
Oh, I'll take my kid to work with me, even though I'll be busy enough to forget important shit.
Ok I'm at work, good thing I'm not leaving anything behind as I leave this car. Hey, what's that noise?
Doo-duh-doo, heading back to my car, getting something, nothing out of the ordinary in this car.
Humming to myself, coming back to my car, seven hours later and hoLY SHIT MY KID IS IN HERE AND HE'S DEAAAD, HOW DID THIS HAPPEN?