With working 8 minutes from home, your kids shouls be fine.
If there were an emergency would they know what to do?
If not, take some time and explain what to do in the case of (blank).
I was babysitting very tiny babies at 12 years old, so I'm sure your kids are capable of keeping an eye on themselves.
Not to be harsh, but how you handle the situation you've been put in is none of your AH's business. If he has a problem, he can fork out the cash for a better solution.
Keep in mind though, that quitting your job (because of the kids) or struggling with debts will not get his attention anymore than what you've already tried.
Do what you need to do for you and the kids, and tell everyone that throws in an outside opinion to go pound salt.
(((Hugs))))
Cece