What my brother did was extremly mean, and I know he will not be getting his laptop back. I am extremly upset that this has happened.
I am truly sorry for all the trouble this has caused. As you said, "lifting it would grant whoever was on the account the ability to further leave harmful messages to other users." I think that he only did this to me, to be annoying. I don't think he'll do it anymore.
If you decide not to lift the ban, that is complelty fine, I was just wondering if it could be any sooner, since I really love chatting with other users.