Almost certainly impossible for you to find a job here. Most unskilled jobs would be reserved for Thai nationals. If you can teach English then you may have a chance.
If he leaves without a re-entry permit then his visa (actually the “allowed to stay stamp” as the visa is used already) would be finished.
Depending on when he’s wanting to return he could get a re-entry permit to keep his allowed to stay date “alive” or he can apply for a new Non O visa for the next visit.
You could come in as visa exempt and convert to a Non O based on being over 50 if you have 800k in a Thai bank account. If you don’t have those funds then an agent will be able to help you.
Ok this post is getting weirder. Why would a Thai citizen that owns land have to divorce a foreigner to keep land?
I’ve not seen a single reference anywhere that London is requiring travel insurance to issue a Non O visa. Why would they? It’s not a requirement to issue one, nor a requirement to get an extension off one.
IF that was a new requirement then I’m sure this forum and others would blow up with posts about it. I suspect it was a “lost in translation” thing.
Your local immigration office should be able to give you a conversion to a Non O (not all do) and from then onwards a yearly extension as long as you meet the financial requirements.
If you can’t then an agent will be able to help for a fee.
Each bank branch manager sets their own rules, so the fact one branch said they “don’t do this anymore” doesn’t mean another branch will. BB has its own issues at the moment so maybe best to avoid them anyway.