You do know that there are Ukrainians here also, yes, and that Thailand isn't bringing any of the Russians here, they're all here voluntarily, same as Ukrainian visitors?
Why would RTAF fighter pilots not be able to fly an F-35 with the appropriate training that no F-35 pilot goes without? The air force already operates many fighter aircraft from the US and Europe.
The most obvious move is to let the US embassy know about his situation, urgently. They won't be paying his bill but they will be able to provide specific advice or recommendations that no one here can.
Maybe my Shopee order of tins of corned beef today was a figment of my imagination, then? Odd, though. because there's a payment from my bank for that exact order.