Already he'd learned a great deal about her past from the talkative ghost. He claimed that Fred wasn't willing to tell them everything about their parents" antics while they were at school, but they knew more than they ever had before. When he asked in his letter if she really thought that the Room of Requirement was completely destroyed after the Battle of Hogwarts, she was glad that she knew it was. Thinking about her son creating his own Defense Against the Dark Arts group with his little mates was terrifying. What had they been thinking when they were young? So much could've turned out poorly.