if he wants more time, check the country of origin of his passport, go to the correct link on the website of the Thai Embassy and apply for the SIngle Entry Tourist Visa there. It does not make sense to go to Bangkok and from there to take a minivan to a border. If he really want to do a border run, ask around in Hua Hin, for sure there must be a service to or Malaysian border or Myanmar border directly.
******************************************************************
*****
-Visa.html