Hi CeeGee,
Thanks, I am looking forward to that drink :ytounge:
I read your original post to remember what you asked. Well, you can bring him everywhere, there is no area that should be avoided. Also if he 19 years old, he is already an adult.
For best experience and first time here, do touristic things during the daytime and enjoy the bars in the nighttime, e.g. diving, fishing, sea canoe, elephant trekking, shooting range, james bond island, ATV, gokart, jeep safari and so on. Rent a driver and visit the different beaches or look around the island. (Or rent a motorbike if you feel comfortable with that, more freedom when looking around.)
The only problem I can forsee is that it may spoil him, and never wanting to go somewhere else for other travel experiences when he start work and earning money himself. In that regard he is maybe too young. Most young people go to south europe for party, girls and booze or do some backpacking to see the world.
But I am sure both of you will have a good time. I know a father who comes here with his two sons once or twice a year, they usually split the time between Pattaya and Patong. I think one of the sons have a permanent Thai gf now. The younger one of them is maybe 19-23, i dont remember exactly.
Have Fun!