His guy already said the relationship was heavy, dude, and they were both tooling one another up, so I think we can garner from that that he is no Mark Poppins. Thailand already has enough issues with troublesome farangs. He might have a stamp in passport, a doc, both or none. But if he must I would get a Thai to call immigration in Bkk and drill down. Probably best not to ask his misses though.