Who was the first actor to play Batman's sidekick Robin?

SQinfoNUTS, according to wikipedia "Douglas Croft died at the age 37 on October 24, 1963, at the Palomar Hotel in Los Angeles, California, near the intersection of Santa Monica Blvd. and Western Ave. just down the street from 20th Century Fox' Hollywood studios. He died from acute alcohol intoxication and liver disease."

this person died in their early 30s. what was the cause of death?