Star Pablito Calvo

The little boy who played Marcelino, Pablito Calvo, only lived to be 51. He died from a stroke (brain hemorrhage). I had heard at the time that his death was caused by alcohol abuse, but I have not seen this in any written accounts.
Does anyone have any information about this admittedly not very cheerful topic? I just want to know if he was affected by Child Star Syndrome in a possibly life-shortening way. He seemed like a nice guy.