Glad I could be of some help. You probably have already seen the 2nd World War enlistment of Eugene Haller, born 1919 in Ohio, 4 Aug 1941. He is single, no dependents and enlisted in Detroit. So that may be of some help. Perhaps his military papers will tell you where he went after the war.
I also found a death of a John Haller in Oakland county (this is north of Detroit) on 16 July 1957. I also found this article to be curious:.http://www.trailblazersww2.org/units_276_accounts_haller.htm Hope you can view it. There is a John L. Haller listed as a member of 276th Infantry, Company A on Dec 31, 1944. This may or may not be your guy.But it does make for interesting reading! Good luck in your search! I will look forward to your progress.