1. He was diagnosed with brain cancer in August 2013. According to The Associated Press, he had surgery at Houston's University of Texas MD Anderson Cancer Center to remove a lesion and received radiation and chemotherapy treatment. He had a relapse earlier this month and was admitted to Walter Reed National Military Medical Center in Washington.

>> RELATED: Beau Biden, son of vice president, dies of brain cancer

>> PHOTOS: Beau Biden through the years

Beau Biden was preceded in death by his mother, Neilia, and sister Naomi, who were killed in a car accident in 1972, according to CNN. He and his brother, Hunter, were injured in the wreck.