550th Airborne Infantry Battalion was tactically attached to 17th Airborne Division for brief periods. The battalion is mentioned in "THUNDER FROM HEAVEN: The Story of the 17th Airborne Division 1943-1945". Originally published in 1947, the book has been reprinted by Battery Press. You should be able to locate a copy through one of the book services on the 'net. You may be able to borrow a copy through Inter-Library Loan.
Certain members are eligible for membership in the division veterans association. Perhaps the association would have info on your man and/or can assist in locating some who remember him.
17th Airborne Division Association 825 Newberry Street Bowling Green, Kentucky 42103-1580