What Visa Should a Foreigner on Marriage in Thailand Apply For?

he can apply for a yearly extension by showing that he has 400K baht in a thai bank account in his name only for 2 months before he applies and by turning in the documentation required at the immigration office.

He can apply for this extension when he has 30 day or less left on his current 90 day entry stamp OR seeing as he's on amnesty now he can do it right off that if he meets the financial requirements

Send him to the immigration office in his area to get the hand out listing the requirements for a yearly extension based on marriage..

You are confusing a year-long, multi-entry VISA <- that you buy at a thai consulate in another country (and which you can get at some consulates without showing proof of funds) with a yearly EXTENSION OF STAY <- that you get from the immigration office inside the country (and which you DO show proof of funds to get)