No, my uncles say he never became an American citizen.
He also had a wife and son in America at this time.
He wife Anna became a citizen several years after his return from service.

It makes us wonder why he was traveling back to Hungary.
perhaps his parents were ill or in some kind of trouble in the final days of the war. We can only wonder...

Why leave his home in America, during WW1, and travel through Europe?
It is an intriguing question.

Thanks you once again for spending so much of your time with my questions!