You’ve said down thread that he was just joking, and he isn’t going. Good!
If he changes his mind, here is my tuppence worth.
I used to live in Asia for a very long time as an expat. I have spent a lot of time in Thailand. I’ve heard it all before. Some men openly go to seedy places for the cheap sex with young girls. Others go on lads weekends, or stag do’s with no intention of cheating, yet they will get caught up in it some way or other.
The first question I would ask is where are they going? If it is some lovely family resort, or classy 5 star hotel in some beautiful location then fair enough. A few lovely days in the sun, and some culture, although they probably will still be able to locate it. If we are talking Pattaya, Bangkok (Oh the irony) or Phuket, then this is not just red flag, it’s a whole other level. Even if they go with no intention of sleeping with an exploited girl (often coerced by the men/ pimps in their own family to make quick money) they can quite easily get caught up in it. The sun, cheap booze, young skinny beautiful smiley Thai girls and egging on of their relatives can quite easily end up in renting one of these ladies or boys.
The second week I moved to Asia, I spent a week in Phuket with my DH’s company, and I was so disgusted with what I saw around the pool, in the streets and out and about, in bars, and the way women were treated and exploited, I had a massive argument with my DH and nearly left to come back to England.
In a nutshell ,with what I know, if my DH was going to Thailand on a lads holiday, he could pack all his bags as he wouldn’t be coming back.