I found this, which would appear to be him:
PHILIP D THRIFT was born 29 December 1956, got Social Security number
248-08-9399 (indicating South Carolina,) and died 10 May 2003.
It is from this page, created from the SSDI for all born on that date:
http://ssdmf.info/by_birthdate/19561229.html
Though with the SSDI now locked down, I doubt that site is being
updated any more.