I think you can take it for granted that Edward was drunk. He had just been to a party where alcohol was flowing like wine (all right, all right). None of the political Kennedys, Jack, Bobby, or Teddy would be likely to come out of that environment sober.
And I doubt that Edward M started out with the intention of becoming a submarine commander. It just fell his lot when his Oldsmobile decided to plunge off Dyke bridge, no doubt of its own volition.
The thing about which a lot of us at the time were incredulous is that Edward M Kennedy left the vicinity of the 'accident', went back to Edgartown (how he got there is another question mark), and at no time prior to discovery of the drowned car reported what had happened to ANYONE who could have helped.
In fact, the evidence was that he seemed to be trying to prepare an alibi, asking some hotel help loudly about the time in order to establish his presence in Edgartown.
I still view Edward M Teddy Boy with total contempt.
But I don't care if the building is named after Bobby boy. He has achieved immortality in the public mind by being assassinated, and nothing will change the public perception.
Bobby wouldn't have gotten the nomination even with his victory in the California primary...Humphrey would have been the nominee anyway. Bobby would have gone back to being senator from New York and maybe the fatal party on Chappaquiddick Island would never have taken place.