Hello, I'm on a nonO extension based on Thai wife and child. My American father is going to be moving in with us. I read that it is theoretically possible for him to also get a nonO family visa through these family relationships but I have my doubts. Has anyone done something like that?

I know the different paperwork and financial requirements of the different visas/extensions, but for anyone who has experience with both extension types, would retirement based extensions be easier or more difficult in terms of queues and potential additional evidence requests (in Chiang Mai)?