to apply for a Non-Imm-O outside of Thailand, he must use the Thai embassy or consulate in his home country. He cannot apply in one of Thailands neighbouring countries, unless he is a resident there
Contrary to above posts, there since February 2022, is a health insurance requirement for aplications for a Non-Imm-O Visa in the threadstarter's home country USA Just NOT YET for extensions out of this visa. . . . . . . . . check here, Thai Embassy Washington DC:
what Immigration asks from you is a Thai family court decision that grants you the paternal rights for your half Thai children. The birth certificates and the custody documents from another country are not enough. Once you have a family court order, you can go for the 1-year extension of stay based on the custody over half Thai children. The process by the Thai family court might take some time, though
if you do a border run and a re-entry just on or BEFORE the Visa expires on 3rd of June, you would be stamped in another 90 days, admitting you until September 2 at the utmost possible. Then just before that, you could use the 60 days family extension, taking you to November 2. Just kindly note, thank you. . . ooops, I just saw that Tod Daniels already posted this option