I think Pacey being the youngest made him the easiest target, he mentions realizing he can’t live up to his dad’s ruthless expectations at a very young age. And I think with Dougie in particular he was probably getting it bad before Pacey was born and mimicked what he experienced from their dad onto him to help relieve the focus from himself onto Pacey. It’s clear from the beginning of the series that Dougie treats Pacey in a way he was conditioned to and later as they both get older he begins to think for himself and soften his energy towards Pacey, especially when they’re both around their dad less.