Dual citizen, but his home country does not allow it?

[No more traveling for me]

I am a US citizen by birth.
I brought my wife and stepson back to the USA with me. They both have green cards. I adopted my stepson two weeks ago and changed his name. I already submitted a request to change his name on his Social Security Card. Once it comes, I will get his state ID. I have an appointment to get his passport and will soon get his birth certificate as well.
Myanmar does not allow dual citizenship.
His old Myanmar passport is in his old name. Myanmar does not know I adopted him. How can he visit his grandmother?
This will be complicated. His airline ticket will be in his new name. So what can we do? I was almost thinking he could fly to Thailand, then go from Thailand to Myanmar on his Myanmar passport. He could return to Thailand on his Myanmar passport, then leave Thailand again on his US passport.
I think that will not work, because he cannot leave Thailand under his old name if he never arrived. Also, when he returns to Thailand on his Myanmar passport, he will leave on his USA passport, so under his old name he will just vanish. Damn that is complicated.

Surely someone has done this before.

[Enub4]

I don't have experience with Myanmar law but I can tell you what can happen to some Spain nationals that get US citizenship, if they do nothing they will no longer be considered Spain nationals and there will be no problem to visit Spain with US passport.

So my question is, does Myanmar have something like that? Can't your son travel with the US passport all the way? I read people born in Venezuela can't renounce nationality and people from Mexico (they allow dual citizenship) must always enter the country with the Mexican passport.

[ronmony]

He can use his old passport to go Thailand and then to Myanmar and in return to Thailand he can use his new passport (if Thailand do not need visa for Myanmar and US citizens) , like a dual citizen with name change in other country, but if Myanmar find out his new passport, what will be the penalty? I think it is better he travel with his new passport directly to Myanmar and if necessary, request a visa for Myanmar as a tourist.

[Enub4]

Each country has its own laws, sorry, I don't know about Myanmar. Good luck.