you cannot use the combination method (income & deposited money) for an extension of stay based on marriage, if that is your plan. It is deposit OR income
in case he needs the full 2 months for seasoning the 400,000 THB, he cannot do so with the extension starting at September 15. He should go back and challenge it. Be very polite but stand your case
it is not a visa. The 60-days visit family is an "Extension of Stay permit" and not a visa. It is a "hard stamp", though. With this he has the chance to apply for a 1-year extension of stay permit based on marriage which requires 400,000 THB to be seasoned for two months. Which is a CLOSE call if they started the extension from the 15th. He should have challenged it
according to the rules, you will be given the 30 days starting from September 27 as day number one. IF your application gets approved. IF they find out that you indeed can return to your home country, your application will be denied and you need to leave Thailand
. . . you didn't "renew a visa". You got a 1-year extension of stay permit. It has nothing to do with the amnesty, so your extension starts with the day you apply for