Go to the Bangkok Bank main branch on SiLom road, then after getting an account there also get one at Kasikorn Bank. It is very convenient to have more than one account at different banks.
don't believe all that hype. Thailand trusts you paid income tax on any money you bring into Thailand, until you prove them wrong, especially concerning retirement. All Thailand cares about is that there is a paper trail of all the money you bring here.
they aren't changing it. If they were actually going to do it they would have done it right after the Songkran holiday ended, and the slow season started.
be fully aware that to extend the DTV inside Thailand you need all the documents you used to get the visa updated. It is much easier to just do a border bounce, where no documents are needed, except your DTV printout of the PDF.
I'm pretty sure he needs his approved first, as that is how it is with the type O retirement, and trailing spouse, if the spouse is under 50years old, as now it is getting to where the different Thai embassies want both to have retirement visa extensions if over 50. Even though it is an e-visa system, the applications for each different location are processed by that embassy. They are not processed at one location for everything, and treated the same. It is still embassy specific.