Why was Richard Pelzer abused next?

YES HE WAS but not that much as David well i can't say that

after the father left... Richard was target for the pain

and some more was left because of David.

But his mother had to find a way to get David in a mental instatute or a crazy house

so i say yes

he also was abused from all the booze his mother drank and the mother needed a next victim since David left.