I'm looking for any info on my grandpa. He died in 1956, his name was Harry Maybank. Born in TX?

He never told anyone anything about his past. The stuff we were able to dig up was his National Guard Service and WWI fought with the Army. He fought in France. He enlisted in Buffalo, NY. We don't know his birth year. We still don't know where he was born, his ethnicity, any family of his. He married my grandma when she was only 16, and he was much older, like late 30s. We've been looking on and off for years. My mom does geneology, but she's run into several brick walls. Any help would be great. By the way, he was caucasion.