AITA for giving my brother a fake password?

So my brother and I are both in college and we both go home on the weekends. We share a Netflix account and such so we can split the payment. My brother has to constantly be logged in on all of his devices AND he has a constant stream of girlfriends. When he brings them over he wants them to have access to the tv in their room so they can watch Netflix if they want to. I dont care if he changes the password to give them access. What pisses me off is that he gives them access to EVERYTHING. I woke up one weekend and all his new girlfriends social media was popping up on MY phone because she logged into everything using the Netflix password. I could open up all her social media and see all her friends and followers and her DMs. I was pissed I could get into her DMs and I told my brother to never do that again. <br><br>Well, he did it again. I was trying to binge a show and my brother had changed the password. I asked him for it and he said that the new password is a mix of the first letter of his girlfriends name, the last letter of his name, and our moms birthday. <br><br>Instead of writing it down, I just put it in my password manager. I made it more complicated by changing the first letter to B, the last letter to Y and our moms birthday to the day before her birthday. So instead of it being F, Y, 8/12 it is now B, Y, 8/11. <br><br>The next weekend my brother came to me and was pissed. The password wasnt working and he had to re-set it and now his girlfriend couldnt get into anything. I told him the password he gave me didnt work and he got mad at me for not writing it down. He said that he gave me the new password and if i didnt write it down correctly that is my fault. I told him that I did write it down and that must be why it wasnt working. He told me that I should have just written down the correct password instead of making my own and I could have not had this problem. I got pissed and told him that I gave him the correct password he gave me and if he gave me a fake password then it is his fault. <br><br>He thinks I am an asshole for giving him a fake password. He said there is no real reason to do that other than to be an asshole and its his password and he can change it and give me a new one if he wants.