If your father has not, he should look into the Gamewardens of Vietnam. I think there are more PBR's sailors there than in any other veteran's organization. I have gone to a couple of their reunions and they are great people. I served on a support LST for deployments to Seafloat and Solid Anchor in 1970 and 1971.
He used to be an officer for the National board. :-) You likely know him. I was actually wearing my TF 116 t-shirt yesterday. God bless the Brown Water Navy!