I feel for you, but as others have rightly said, you need to get your ducks in a row and start planning.
Your husband is not proud, he is a misogynist. The way he treats your Mum and sisters is appalling, and now grasping at straws by saying he heard of some idle gossip and he changed his opinion of her? Really? Have a serious think about that. Your Mum, who sounds kind and has the grace to put up with his obvious rudeness around her and your sisters?
I sincerely hope if you have daughters, you are going to redress some of the balance here, before they learn their place in their Father's world. As for your sons, ask yourself what kind of role model their father is to them? Treat women like shit and be disrespectful at every turn, yet expect them to scurry about putting solutions in place for him?
The fact that you laughed about the child's passports and said "you lost me" at the (very real) suggestion, makes you come across as naïve at best.
You have bigger problems than your husband's "pride" I am afraid.
You have come onto a public forum to ask for advice, and most of the advice is sound, yet you have continued to insist that you must have your husband's back and go to lengths like have a legally binding document drafted and present to your Mum without thinking that is quite ridiculous under the circumstances?
With respect, please wake up.
Use your Mum's very generous loan to sign up to an intensive driving course and get your license. Follow the advice re council tax, benefits, child maintenance, etc.
Your husband's latest tantrum is him showing you who he is. Believe him.