Final answer:
Dr. Hector P. Garcia founded the American G.I. Forum, which was key in combating discrimination and ending the segregation of Mexican Americans in Texas.
Step-by-step explanation:
The reformer who founded the American G.I. Forum to help fight discrimination and played a large role in ending the segregation of Mexican Americans in Texas was Dr. Hector P. Garcia. This organization was instrumental in advocating for the rights of Mexican American veterans and addressing broader issues of discrimination against the Mexican American community. While Cesar Chavez and Dolores Huerta were influential leaders in their contributions to labor rights through the United Farm Workers, and played significant roles in the Mexican American Civil Rights movement, it was Dr. Garcia who established the American G.I. Forum.