Actually you would have to request his records here-
http://www.usmm.org/contact.htmlMerchant Marine records are held in a separate location from those of military records
Include Name, Date of Birth, copy of Death Certificate if deceased, Social Security number, Address, and Z or Service number.
Commanding Officer
USCG-National Maritime Center (NMC-421)
ATTN: Correspondence Section
100 Forbes Drive
Martinsburg, WV 25404