OOPS - I just found a copy of their marriage certificate and it doesn't show John's parents. No need to spend the money.
Death records in Montana were inconsistent prior to 1907.
There is a Montana State Genealogy Society volunteer who specializes in Lewis & Clark Co. Al Stoner, Alasto@aol.com
If he doesn't find a death record, ask him if there were any newspapers in the county at that time. Successful Searching!