Factual error: When Frankie Howard died he was not alone - he had two friends with him who were either thrown clear or managed to get clear after the crash. Also, it was not his father that was the first one on the scene. Frankie's friends headed off and summoned a man called Doc (I can't remember his surname) with limited medical knowledge he used for the local lumberjacks.
Factual error: In the final race, Red Pollard is shown with a number 9 on his sleeve, indicating Seabiscuit's starting position. In fact, Seabiscuit had the number 1 starting position (this can be seen on historical footage).
Factual error: In the final race, one of the horse's saddle pad flips up in the wind and reveals a synthetic-type foam rubber lining. This was unavailable in 1938.
Factual error: During the times where Red is in the hospital, they show Red several times with a cotton blanket with a certain type of weaving they didn't use until the 1960's. In the 30's they were still using single weave blankets. Kind of hard to explain, but older nurses could tell you.
Factual error: The license plates on the cars were dated TX 1937. I don't recall the movie ever happening in TX and they had not reached 1937 on the time line, yet.
Factual error: Orange twine was shown to tie bales of straw, twine of that type wasn't used until the late 70's or early 80's.
Factual error: When Seabiscuit and crew are returning by train to California after the big match race in Baltimore, the locomotive seen is a distinctive model used only by railroads in Canada.
Factual error: In a scene that is captioned: Tijuana, Mexico 1932; Jeff Bridges is being driven in a 1936-7 Buick.
Factual error: The doctors tell Red he has broken his leg in 13 places, however the X-ray shown later is not indicative of an injury of that nature. The two fractures you see in the X-rays are considered non-unions (fractures that aren't healed properly and are unstable) but we should also see some type of hardware that would be needed for that many fractures. Surgeons have been using internal screws on fractures since the turn of the century.
Answer: I have tried to look this up, and there is no record of Red's parents. Most likely they just died of old age.