Whilst I don't know the expat community in the city mentioned, i have lived/worked in Isaan for the last 18 odd years. Most people here are either (mainly, not 100%) retired or younger teachers. I would suggest that most will not care that he is gay, but what might give him more trouble, is that he is 'extroverted' because some might have different takes on that and see it as rude, unfriendly, overpowering because they are quiet people (of any gender).
just my two-penneth!