[smirnoffdear]

Thank you for the speedy reply and the interesting link.
I think I may miss this day by the time I return to Thailand, that's a pity.
Would it still be appropriate for me to give gold or money?
How much money should I give, and does it have to be a red envelope?
My friend is very proud and any time I visit he gets upset because I always offer to pay for things, I wouldn't want to put too much money in the envelope and offend him.
I think your idea of a golden Buddha representing the day of the birth is good and it might be more acceptable than cash.