he doesn't actually know what type of visa he has. "Visit family and friends TR visa" whatever that is. So, sounds like he has a SETV which is 60 days + 30. I suppose he could have got a non o marriage/Thai child ( 90 days) but I guess he would of mentioned that. Either way, 3 months to use it.
you don't get any choice in the matter. It's up to your carrier. So you either go back to the country you came from, or, on rare occasions, home country