Dino's drunk routine was just an act. He was at one point one of the highest paid people on TV.
Dean was also supposedly a real homebody. He was devastated when his son Dino died in the Air National Guard flying an F-4 Phantom. They said he was never the same and died brokenhearted because of his son's death.
I'd read that the death of his son pretty much took his joy in life away.