2 people can use 1 Minecraft account.

Yesterday my brother saw my Minecraft account on the server mad-gamble.net, but I have not played. The minecraft account is called CuzImKilla. Then of course I immediately changed my password, but he can apparently still play on this account and wanted to ask if it is a bug. They can reach me under the email justinleyda13@gmail.com. Would be great if they could help me