Who is Alex Dekel from Children of the Flames: Dr. Josef Mengele and the Untold Story of the Twins of Auschwitz and what is their importance?

Although, Alex Dekel was not a twin, he was selected by Mengele because of his Aryan features. Alex watched as Mengele performed surgeries without the benefit of anesthesia. After the war, Alex became obsessed with finding Mengele. He often spent weeks searching out clues to Mengele's whereabouts. When he learned that Mengele was presumed dead, he had a heart attack and died.