Percy nodded, thankful Ron accepted it for what it was. His brother didn't need to know that, after spending some time with Molly, Percy planned on coming back home to be alone again. That is, if she let him - though worse come worse, he could sneak out come nightfall. He was likely the only one of his siblings to never do that while living at home, so she might not suspect him of it.
"She'll worry," he finished Ron's sentence for him. "When you love someone, you worry about them. And you may think you're doing the best thing for them, protecting them, and they may not understand why you're doing what you do, but you do it because you think it will change things. But then they may not understand it, may even hate you for it, when all along you were trying to help."
The whistle blew, and he poured out the cups, seemingly ignorant of his own rambling. Once the cups were steaming the tea leaves, he looked up at Ron again.
"Don't repeat your brother's mistakes. When she argues, listen to her. Tell her you love her every day, as often as you can. And never let her go."