Question: I could not figure out why Red borrowed $20.00. Could someone fill me in?
Question: Does anyone know what historically happened to Red's parents?
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.
Question: Why don't Red's parents come back for him, even when he becomes famous?
Answer: They probably do, it just isn't shown. Alternatively, they could have died in-between the time we see the young Red and Tobey Maguire. That could be a contributor to all his anger and rage.
Answer: Red asked for $10 because he needed to see a dentist, and Howard gave him $20.