Not only was [Lily] a singularly gifted witch, she was also an uncommonly kind woman. She had a way of seeing the beauty in others even, and perhaps most especially, when that person couldn’t see it in themselves.
When a little boy who looked frail and frightened stepped up to the sorting hat, McGonagall didn’t think much of it. She was quite glad to see him enter her house though, because she got the feeling that this little boy would surprise her one day, she just didn’t know it would be that night.
She was called to Dumbledore’s office and was surprised to find that boy sitting across from Dumbledore. As usual, Dumbledore welcomed her and offered her a seat next to the boy.
It was then that she was told about his condition, and saw how he had steeled himself for the reveal, and his eyes looked older than he was, filled with experiences that no child should have to endure.
She made sure to always assign work so that he would have plenty of time to get it done without his condition getting in the way of his school work. She was told that Madam Pomfrey would accompany him to the shrieking shack, but she insisted on going as well every single time. She would stay with him for as long as she could, and every morning after, she would bring him breakfast so he wouldn’t have to wait until he got back to the school.
In the middle of his third year, she became nervous for him as his classmates learned about vampires, grindylows, and other such creatures, including werewolves. One of his classmates figured it out very early. Another boy who McGonagall was sure would be in Slytherin, but was happily surprised to find him in her house. One day as he was leaving her classroom, he called out, “You knew.” They never spoke of it again, but she saw how the boys’ friends stayed with him anyway, and supported him in ways even she didn’t know about.