I myself would consult with an experienced, competent, local lawyer to ensure your interests are protected, that you aren’t being scammed, that you meet all the requirements to use the money for the intended purpose, and that you can eventually repatriate the money if you desire.
A bank wire or cashiers check is definitely the way to go.
You also may be able to negotiate with the receiving bank for a few extra points off the exchange rate.
If he doesn’t have enough money to be insurance, he doesn’t have enough money to pay for emergency health care and therefore represents an unnecessary burden to Thailand… and your friend should probably stay home.