Where To Find Military Records

Funny I just came from visting Gramma, she is 93. Still a spitfire for sure. I would like to find some info on her brother who was in the Navy. I met him almost 27 years ago in San Diego and he showed me pics of him on a US Navy ship recovering the capsule from the 1st Manned Apolla Mission. I tried google with no luck yet, I would love to be able to give Gramma some more info about him. Oh and when I met him in the back driveway was a 68 GTS! LOL