They don't really parent by themselves, you need to instruct them to do it. Toddlers, once they can walk by themselves are pretty independent, you can leave food out for them and they will take care of their own needs, just remember to give them a bath and clean the potty every now and then. Babies need your attention more, maybe it helps if your sims study parenting. I have a sim who appears to be a natural at parenting, always tending to his baby and he even studies parenting on the computer by himself instead of trolling the forums like other sims. Not sure if it's something to do with his traits or parenting skill, some other thing in game.
I'm guessing that that sim of yours, crocobaura, has a couple of family related traits, if he's that attentive to his kids. 😉
