18 Day Extension On 30 Day Visa Exemption Stamp Possible?

[Jayman]

My mate is married with a thai and also has a child. He's here on a 30 day visa exemption stamp and needs to extend by like 18 days as he has air tickets to take the whole family to OZ. He will be getting his non-imm O in OZ on his visit. Is it possible to get an 18 day extension or will he have to do a quick border run?

I have read that perhaps 7 days is the max extension given on visa exemption stamps.

[lopburi3]

He can extend 60 days on basis of wife or child - will have to visit immigration with the wife and proof of marriage. Cost will be 1,900 baht and TM.7 form with photo.