why do you think pony's oldest brother is so hard on him does darry have a right to treat pony this way?

Darry is responsible for Pony. Since their parents death, he's had to take the place of both parents, thus, he looks out for him in a completely different way. He doesn't want his brothers to be taken away and placed with other families, which is a definite possibility in their circumstances. Does he have a right to being over protective and placing high expectations..... yes, he does.