>>He did end up in ND for some time then went to Montana where he lived and died.
When and where in Montana? Can you narrow it down at all? Eastern or western Montana, a decade or a year?
You need to do more research in the U.S. Get his death certificate. Look for probate records, or an obituary. Find that brother. Check immigration records; maybe his destination was a brother or other relative already in America. Don't assume he didn't have the Anderson or Andersen name yet then; he had both names (and likely a few others he could have used) when he came to America.
Post queries on the GenWeb boards for the counties in which he lived.
Tell us more about what you know about when and where he died, wife died, specific places they lived, and we might be able to help.