Old-son

There is a man at my office that bugs me as much as any human being ever has. He's that person that goes on and on about nothing, and you can always bank on the fact that whenever we have meetings, he's going to say something so inappropriate or off the wall that your mouth involuntarily flies open in shock and/or horror.
In the past two months alone, he's told me several times that he could tell I had gained weight. (You never say this to a woman.) Then, when I went on a diet and lost all the weight, he told me that I looked bad because I was beginning to resemble Twiggy. He has a real tendency to humiliate and belittle people for no reason.
Not to mention that every morning, he says to me, "Good morning, Old-son. See how I call you Old-son and not Olson. It's because our job's causing you to age really fast." He explains this to me every morning. Then he laughs for a few minutes and waits for me to do the same. I do not partake.
After I got a haircut last week, he came up to me and said, "Oh no, your hair's thinning. Maybe it's because you're getting older. I guess there's something to your name, Old-son." What the hell?