I wonder if we could use forensic genealogy to eliminate certain hypothesis to where he went. Take the hypothesis that he went to Argentina or Venezuela. And s

I wonder if we could use forensic genealogy to eliminate certain hypothesis to where he went. Take the hypothesis that he went to Argentina or Venezuela. And say that he had children. Then it's possible to find a match between his relatives in Italy with ones in South America no? If no matches are found, then it's highly probable he didn't go to South America.