There were crowds of people all around them, shouting and laughing and jostling him and Regulus didn't like it, not one bit. Sirius didn't seem to mind. He kept hopping from foot to foot and looking over his shoulder at the enormous scarlet train like he was about to make a run for it.
But he couldn't bolt, because mother was gripping his shoulders and commanding him to remember his name and act accordingly.
Regulus wanted to hug his brother but he couldn't, not in front of mother.
I love you, and I'll miss you. Please don't forget about me.