Ancestry has a Rex J Fitzgeald b. 1928 in CA, I don't find a Army/Air Corp enlistment for him on their database or NARA ADD. The Navy and Marine databases for WWII are not online yet. Service Records themselves are for veteran and next of kin only.
I find a 2006 obitury for his sister and he survived her then. Try zabasearch still living in CA. There are a few results with middle name Rex.
Also found this doing a Google search "Rex Fitzgerald"