BritTim

As a general rule, Immigration will always use whatever you qualify for that gives the longest permission to stay. Occasionally, exceptions are made, but your experience, unfortunately, is typical.

Bear in mind that, nowadays, it seems very difficult to stay in Thailand more than a year or two with Non Ed visas/extensions to study at an informal school. Treat that as a temporary solution. If quite certain that you want to stay many years in Thailand, and aged well under 50, the 20-year Thailand Elite visa might well be a good, safe option. Even if close to age 50, people tend to ignore the reality that retirement extensions are likely to have more onerous requirements at some stage, possibly in the near future.

If he arrived without a visa, he was correctly given a 30-day visa exemption. He can extend this by 30 days at Immigration. Most likely, to get any more time than that, he will need to leave and re-enter Thailand which can usually be done most expeditiously, within minutes, at a land border.

There is an official rule that Non Ed visas and extensions for study at an informal school (commonly Thai language classes) are only permitted until 12 months after your last entry into Thailand. You might be able to find an agent who works with a university (probably quite expensive) where the 12 month rule would not apply. Otherwise, I think you were given the correct information by the agent.

Are you going to Penang for a tourist visa or Non O volunteer visa? If you receive a tourist visa in Panang, you will receive a 60-day permission to stay when you return to Thailand, which can optionally be extended for a further 30 days at immigration.