My bro walked in on me. ?

Me n my bro split rent 50/50 and last night I went to shower so did he in his bathroom. My bathroom is in my room so a closed my bedroom door and started to striP down, soon enough I find the shower running my laptop open and me doing my business bare *** naked when all of a sudden I look back and see my bro through a 6 inch crack in the door he's walking away. He opened it and saw me then left. He doesn't know that I know he saw. But when I got out of the shower my bedroom door was closed again. What do I do? Do I tel him? Or just keep quite and hope he does the same?