@Greg **********
Fair enough, but the point was he entered Thailand apparently, in MY scenario, WITHOUT an onward ticket within 90 days. You suggested it was the ticket to Viet Nam, WITHIN the 90 days.
I'm suggesting there's no evidence he had that ticket when he left for, or got into, Thailand, so he shouldn't have been let in in the first place.
But yes, right now it makes no difference............