Clancy was just unwittingly ahead of his time with the idea of embarking a dipper on a smallboy.
The hangar on the Spruances could fit an H-3 (there were tiedown points labelled as such) and definitely fit a 60F (60B's Irish twin). I'm not so sure about the Perrys being able to swallow an H-3 (the folded up 60 just barely fit) and I don't have a copy of the ships resume to look it up anyway. The Navy has embarked helos on hangarless Flight 1 Burkes for short periods, left them out in the weather (obviously) and used a lot of fresh water to fight the salt buildup. I mean tactically embarked with a mini det footprint, not just lily padding or overnighting because of unusual circumstances.
Either way, Clancy's poetic license to have a 60F cooperating with RBJ isn't far fetched at all.