Does the son speak Thai? Maybe some games/toys that can be shared with the local kids and maybe left behind. Frisbees, footballs, water guns...... The locals here like Uno. A volleyball kit with a net would be popular.
You will be stuck drinking Lao Khao with the men while she works. Do not toast individually, only drink when everyone drinks. Try to mix it with soda to take the edge off.
Lots of temples to see. Be careful about getting stuck with the bills for the family shopping excursions though. I let the Mrs. handle the money because she can say no where I can't but that depends on your relationship.