"It could create a time paradox that could unravel the very fabric of the space-time continuum and destroy the entire universe! Granted that's a worst case scenario. It may just be merely localized to our own galaxy." "Well that's a relief."
This article's subject originates from a draft screenplay. The material is not considered canon but is notable enough to be included here.
It is possible to conclude, from material outside the films (non-canon), that there is an Abraham Lathrop. In commentary to Back to the Future Part III, Bob Gale says (during the scene where Doc and Marty enter the Delgado Mine) "In case you're wondering what the "L" stands for in ELB...Lathrop. Doc's mom's maiden name.". In addition, a 1988 draft of the Part III script includes Doc telling Marty, "I used to spend summers at my Uncle's ranch. Uncle Abraham taught me how to ride and shoot and rope. He used to say to my parents, 'Young Emmett belongs in the fresh air and the open spaces; not in a school room." It's possible that Abraham may be a Von Braun. The 1988 draft script makes no mention of Doc's mother being named "Sarah", nor that his mother had a doll named Emma. Although there are statements in imdb.com, on Wikipedia, and on fan sites that "an early draft" referred to "Sarah Lathrop", this cannot be verified by the lone draft script for Part III that is online.