John Cazale was 38 in The Godfather Part II when he played the character 'Fredo Corleone'.
That was over 49 years ago in 1974.
In 1978 he died aged just 42, starring in 10 films in his career, 6 of those after The Godfather Part II was first released. If he were alive today he would be 88.
In The Godfather Part II, I think John Cazale looks: