There are over 40 listed on the Social Security Death index ( if he was from the US) it lists thier social security number and last known address, and thier bith date but there was no Jan 12, there were some Jan, but not the 12th. I have no idea if any of these are him, but if you would like to look and see if any info looks familar
Social Security Death Index - Free Access - New England Historic Genealogical Society(NEHGS)
And of course doing a who/where search I came up with 61 names of William Rex living in the US today. You can look though these by your own search at
The Ultimate White Pages
I guess with lack of any other ideas, you can start by calling down the 61 living ones, take a couple days and see if any match.