If you’ve got a Thai husband you should apply for citizenship which is fairly straightforward for foreign women to get . Means you won’t have to worry about visas.
Sounds like he has a Thai parent and getting extensions based in that? Then if so he can enter on a 30 day visa exemption and then get a years stay. This article explains it.
She can enter on a thai passport at any time with any validity. She’s not a foreign national so the 6 month rule doesn’t apply to her Thai passport. As others have said it’s possible to enter on an expired passport and get it renewed in Thailand. It take 3 days to get the new passport in the mail or you can pay extra to get it on the same day.