All else notwithstanding (and I am bitterly disappointed in each and every GOP Presidential candidate in this millennium) McCain did go off to VN when others rushed to Canada. And, he does have a family who loved him and who grieve today. May his soul find the eternal peace that avoided him in this life.
No, McCain walked into Annapolis in the 1960's based on his father's rank (Admiral, aviation, USN, Korean War and PACFLT), and his grandfather's rank (Admiral, USN aviation, WWII). He had four terrible years at Annapolis, graduating near the bottom of his class - again saved only by his father's rank and his grandfather's rank.
Once graduated, he had a terrible US Navy reputation as a drunk, a troublemaker, with many punishments and criticisms for insubordination and lack of discipline (driving, acting up, disorderly, etc.) John McCain was a terrible flyer - but was a Cold War ace pilot (for Russia): He got shot down in, burned up, crashed (in Spain, while showing off at low altitude), destroyed or ejected from five enemy (er, US Navy) airplanes.
No one else - without John McCain's name and connections - would have been retained as an pilot. Few would have even been retained as even an LST deck officer.