Until this time, Richard seemed to regard Regan, as a fairly benign rival for his parents' and grandparents' attention. She was always there, but seemed to be happy sitting on the side-lines watching, as he exercised his authority over the toy-box, and table-tops. Apparently, he now realizes that he has to share not only his belongings, but center-stage as well, and he doesn't like it.
Richard has chosen to deal with this intrusion, in the fashion that any red-blooded American boy would, by walking over, not around his doe-eyed little sister. Each and every time he plows Regan over, his parents respond by pointing out the infraction, leveling some form of punishment, and insisting upon an apology for the brutish behavior.
We may feel regret for hurting someone's feelings, or recognize that we've behaved badly or inappropriately, but when it comes to expressing remorse, and making amends, many either stiffly refuse to apologize, or offer an excuse for the bad behavior. Like peanut butter that's just too darn dry, many of us are just too arrogant to swallow our pride, and openly admit that we've done something wrong!
A sincerely expressed apology, never diminishes one's stature. It's the guilt and remorse that we feel for not owning up to our own transgressions, that ultimately make us small. Considering how hard it is to choke-out a few short words of apology, I'd say that making one, ought to be considered both cathartic and courageous.
With his parents' consistent and persistent intervention, I think Richard will quickly decide that being a bully isn't worth the trouble it causes. As for making apologies, I can only hope that as he matures, he understands that it's as important to express them, as it is to hear them.