He Is A Night Security Guard But His Colleague Exposes Himself While Sleeping

My people pls I need ur advise, am a night security guard, am a very young man my colleague do always expose himself while sleeping & during his duties I ve told he several occasions to stop exposing himself because it is very dangerous he refused. he is far older than me, because of the way he respect me I don't want to report he in the office but now is getting out of hand ooo. Pls what should I do now?