BRICS is not the threat people tend to think it is, for starters, and Thailand really doesn't want to fracture what is called the "special relationship" it has with the US. I wouldn't worry at all.
don't worry. You're fine with Navy Federal. I use Schwab and Fidelity who are also fine with an overseas address (outside black listed and some gray listed countries, of course, but no danger of that in Thailand.)
as far as banking, the best advice is to use an institution, like Schwab, Fidelity, Navy Federal, etc. that allow an overseas address. I've moved everything to Schwab and Fidelity.
A couple things. Six weeks off of work for a falang means they need a work visa. If they don't have one, you have them by the proverbial cajones. If they do have one, I don't think they can go without working for 6 weeks, in which case you have them by the proverbial cajones. Offer half the vet bill paid directly to the vet and hang the visa over his head.