I had found that record also. Much does seem to fit. No one knows anything about a brother, Karl. We do think he worked with metals, so that fits. There is very little knowledge of him to piece together much.
The adoption papers say he was naturalized, but the family says he was not. So any immigration papers may not be him. Or may be him!
What we do know is that he is not the Alfred Berner that lived and died in New York state. There are records of that Alfred along the way.