Several alternate versions of Douglas Davenport exist.
This Douglas was injured in a car crash that killed both Kaz and Alan's parents. He somewhat did it on purpose because Kaz was resisting his pal Krane. However, after Krane became evil, Douglas regretted it. This made Krane mad, so he arrested both Douglas and Donald. As Donald lay dying, he begged Douglas to take his name, and start a new life in Denver, Colorado. However, Krane was an avid Harry Potter fan, so he knew at once Douglas was a fake, for he had anagramed Donald's name into Tom Mikardroll Vadenporan Riddle. Krane declared Douglas the reincarnation of Voldemort, sending him back to prison.
Douglas became the adoptive father of Cory and Eric Matthews when Maya and Riley brought their younger selves to the Science-Music Mixer in 1988. This resulted in the boys staying, becoming siblings of Maya and the Lab Rats.
Douglas was saved by his brother from Victor Krane and the evil Ricardo, and thus both became hated by the Krane crime family. This led to years of abuse, and Nick Krane (Krane's bro) paralyzed him in 2000. Douglas' organs and systems continued to work, and while his neck muscles became unable to hold up his head, he could still talk, breathe, and move his hands. The same fate befell Donald. Douglas was abused so much, that he finally agreed for them to run Adam, Bree, Chase, and Leo out of town so they'd stop.
Not long after Douglas' birth, his parents divorced so that Carter Davenport could marry his dream girl, Sarah Perry. However, Sarah only saw him as an older brother, and fell for Douglas instead. Douglas became the benevolent dictator of Centium City, ruling with an iron fist. However, he was merely Sarah's pawn in a dystopian society that literally banned everything cool.