What are the requirements for a Canadian citizen to obtain a multiple-entry Non-O visa for Thailand?

Ask for a friend.

Good afther noon all. So my friend candian passport holder. Flew in to thailand yesterday without a visa afther allready doing 3 TR visas.

He was told by the immigrations officers that he would be denied entry next time unless he gets an non o visa. His reason for being in thailand is to be with his gf (thai natinal). There not married but are willing to do so. Meeting any momey reqirments is not an issue. He has a company abroud that runs itself

So the main qestion is what would he need to get a non o visa prefrably multiple entry as he want to leave the country every month or 2. And are other visas an option the immigration officer told he that only non o would be accepted.

Kind regards