What can we do with a boss who urinates in a cup in his office and then dumps it in the kitchen sink even when we (all women) are sitting there eating lunch?

We are certain of what is in the cup because it smells, is yellow, and it sits right on his credenza in plain view. He’s even left it outside the office, forgetting to empty it.

A few weeks ago I was washing my lunch dishes and he dumped it right on top of my stuff. I was pretty much in shock, I just couldn’t believe it.

Is there something wrong here that I’m not getting? He’s the owner, the boss, in his 70’s, and very respected, but I don’t understand this. No one knows what to say. We feel that if we said something, he would deny it and since he’s the boss, who knows what would happen. Is there any way to approach this? The only other males in the office are related to him. Someone did mention it to one of them, but nothing has changed.