Something akward happend last night........?

My brother was meant to watch a movie with me and hang out because my Dad is In Milan and Mom is away too.But decided to have a date last minute.I Decided to take a nice long bath in the dark (I know, I'm weird.). Then all of a sudden Lennon (My bro) opened the door, but thank god he didn't turn the light on (The hall light was on). He was fully naked! I dipped down in the bath so he wouldn't notice me. He grabbed the box of condoms and put one on in front of me! He then sprayed some deodorant on himself and walked off. Should I tell him I saw him. Or would that embarr him? I'm mortified, and to be Honest, I don't want to tell him either. He's 17