I want to share a story with you. When I reached the age where I could choose my clothing, my mother suddenly became very critical of everything I wore. While I was still young, she had a bit more control but, as an adult, when I moved out on my own, the criticism became even greater. Despite wearing fashionable, decent attire, my mother couldn't stop being critical. My pants made my legs look too skinny; a shirt made my chest (read: breasts) look too big; many pieces were ugly. Those are but a small sampling of the things she said because I don't have the time nor the inclination to write them all out here.
Each and everything she said, hurt. It wasn't constructive criticism, it was flat-out telling me how everything was wrong. Not only did it destroy my self-esteem as a teen but it assured I had zero as an adult and had no effect on getting me to change to what she liked because as an adult, I was still passively aggressively rebelling against her cruelty.
Fast forward to when my oldest son was in college. I thought his choice of attire was "too small" or "ugly." I blamed it on young adults not having any fashion sense. Without even realizing it, I was doing the same exact thing to him that my mother had done to me. Finally one day he said to me, "Mom, no matter how often you tease me or give me a hard time, I'm going to wear what I want to wear. You choose your clothes, I'll choose mine."
Now, I hadn't quite started changing yet, but his words hit me like a ton of bricks and later on when I began to understand where my life was headed (that is, without my adult children in it), that was one of the first things I changed. Do you know what happened? Within months his entire choice of clothing had changed. You know what I understand now? My son was rebelling against me just as I had my mother. When I stopped criticizing his choice of clothing, he no longer subconsciously felt the need to rebel.
Your son is an adult. Not even a young adult but very much a grown man. Leave him alone. Like my son said, just as you get to choose your clothing, so does he. If you don't like it, fine but keep it to yourself, and you just might be wind up pleasantly surprised at the outcome.
It should be said, however, that as we age, we lose a sense of what is in style. Torn jean bottoms are trendy these days. And maybe his shoes are just comfortable. My fifty-year-old husband has a pair of work boots he refuses to replace because they are the most comfortable shoes he's ever owned. It's not to my liking but he's an adult, and it's not my choice.
Let go. Stop trying to control your son. You had ~18 years to guide and instruct him; now it's time he does what he feels is best for him. And as for dating, the right woman will love him for WHO he is, NOT what he is wearing and that's exactly what you want.
Please, don't make the same mistake I did. I almost caused my adult son to walk away from me, and I did walk away from my parents. Ask yourself, which outcome would I prefer?