Complex sentence: After his success with "Don't Close Your Eyes," Whitley was said to be a promising new artist; however, in 1989, he died of an alcohol overdose at the age of 34.
Split into simpler sentences: After his success with "Don't Close Your Eyes," Whitley was said to be a promising new artist. Sadly, in 1989, Whitley died of an alcohol overdose at the age of 34.