It would work if he was paying for it under the table. Many guys use Pattaya to pay under the table but live in Buriram. Buriram Immigration operate as agents for themselves and charge 16000 for a Retirement Extension.
If the visa is obtained 'under the table then it's not legit. For an 'under the table' visa/extension one is able to do it anywhere provided you find a bent immigration officer which shouldn't be hard.