@Tara *****
he can 100% get a 2 month TR (tourist) visa and then later extend it for another month (1900 baht). Then, after the 3 months In Thailand, he can then further extend by changing his visa to an education visa (learning Thai, Muay Thai etc), for a further 6 months or 1 year. Those visas are 20,000 for 6 months and 35,000 for 1 year. Or even get a volunteers visa, many of which can be free. But he would actually have to do the learning or volunteering as it can be checked.
STV has a $15,000 in savings requirement, which you have to show consistently saved for 6 months and show bank statements to prove it. TR visas, you need to show $30 dollars for every 2 months worth of stay, $1,800...