Sounds like you are gonna have your hands full. If he speaks no Thai, and neither do you the English camps for Thai kids are going to be way above him, and he will find the games boring.
Its a major problem here as there are little to know sport programs as well. Plus the daytime temperatures are over 35 to 40 everday until the rains start mid April.
I wish you luck. I am going the opposite way I am taking my English speaking kids to the states.