Boots, I ended up doing just that and it sort of worked. The conversation didn't go as well as I hoped, but he finally said he'd get the car seats under control this week.
Ninetales, good to hear I'm not alone! DH is actually usually pretty good around the house (neither of us are super clean people), but he is definitely a slacker when it comes to dog care and putting his clothes away. So frustrating! And he's stubborn, so pushing him just does nothing.