Dennis previously worked at BNSF as an engineer. He also worked at the Amarillo Police Dept. He proudly served in the U.S. Navy during the Vietnam War.
He was preceded in death by his parents, A.N. and Lucille Alexander; and a brother, James Alexander; and a son, Dennis Alexander, Jr.
Survivors include a daughter, Kelsey Rivera and husband Fletch; a son, Olaf Alexander and wife Pegah; a sister Brenda McCullough and family; and a brother, Terry Alexander; and his ex-wife, Deanah Alexander.