I’m currently in Thailand. Been here 14 years on a non-profit volunteer visa. My wife and our kids are all American. Kids have grown up here.
We’re going to the States in May. Planning to return in September.
My visa expires in March of 2022.
My 16-year-old son’s visa expires in August because we just renewed his passport.
I went to immigration yesterday (in Surin) to ask them if they would extend my son’s “follower” stamp/visa “ผู้ติดตามครอบครัว” to have it expire at the same time as mine in March of 2022. They told me they could only do it 45 days ahead of time which is late June. I will be in the States then.
I’m trying to figure out what I need to do to extend his follower stamp/visa while in the States. In the past we just send the application to a Thai consulate and they give the kids a visa that allows them to return to Thailand which then gets changed to a “follower” stamp once we’re back in the country. 
Is anyone familiar with how this process works now during the time of COVID-19? We don’t want to have to apply for a separate visa for our 16 year old kid because of all the complications of the ASQ and COEs and such. Any thoughts?