Original: In January 1886, Lenin's father, a schoolmaster, died of a cerebral hemorrhage, and, in May 1887, when Lenin was 17 years old, his eldest brother Alexander was arrested and hanged for participating in a terrorist bomb plot threatening the life of Tsar Alexander III.
Simplified: In that year, Lenin's brother Alexander Ulyanov was hanged for his part in a bomb plot to kill Tsar Alexander III.