I (M, 20) have been friends with Sarah (F, 20) for years. We were always like brother and sister, did a lot of things together and supported each other. For a long while Sarah was living with her grandmother because of problems with her parents. About ten months ago, her grandmother had a stroke and had to move into a hospice. With nowhere to go, my parents and i offered her a vacant appartment in our house - rentfree. We helped her move in, renovated it to her liking, and treated her like a member of the family. At first, everything was great. She often ate with us, spent time with us, and her cat could roam freely between the apartments. But at some point, she started going out more and more - which was fine. She has her own life. The problem was that she also stopped taking care of her cat. The animal peed on the laminat flooring, completly ruining it. When we brought this up. she said harshly. "It doesn´t matter anyway." But it did matter to us, and from then on, her responses became colder and colder. On my birthday, the only message I got was, "Happy birthday despite everything." I asked what that was supposed to mean, but she didn't answer. The next day, she suddenly announced she was moving out with no explanation. This made me so angry that, in a fit of rage, I packed her things myself. During the move, she completely ignored us. She only gave us the key at the very end, and when my mom asked how she planned to replace the damaged laminate, she just shrugged her shoulders. At that moment, I just blew up. I told her to her face that she was a bad friend, that she had become cold and dismissive, don´t cares about her cat and that she couldn't even take responsibility for the damage she caused. She started to cry, told her friends that I was mean, and everyone left. During a final inspection of the apartment, we even found a used sanitary pad stuck to the bathroom wall. A week later, I wrote to her, asking if she had settled in and if we could talk. Her answer was that she was feeling much better, that I should not contact her anymore, and that I was an "extreme asshole" for calling her a bad friend. Then she blocked me. Now I'm wondering: Am I really the asshole here? English isn't my first language, so please excuse any mistakes.