I don't think you need to be paranoid about your feet. It is a good idea to go to a Podiatrist regularly. I see one every 10 weeks. He cuts my toenails and tests the bottom of my feet for signs of Neuropathy. He also trims excess skin that grows around the nail. It is not a good idea to do this yourself, you can cause more problems. As far as your co-worker, you don't know what kind of BS control he has or how he handles his D. If the boots fit properly they shouldn't cause any problem.
I think a podiatrist is the best person to deal with cuticles, callouses, and excess skin. They have the proper instruments and experience. I also think it's okay to get a pedicure, but not to have them do any shaving or trimming - just a nice soak, massage and some hot pink polish!!
Foot care is crucial. I think your paranoia is justified. First, get diabetic socks, it you don't have them, already. Then, find the workboots that are the most comforable. Preferably something that breathes a little. You should rinse and dry your feet every night.
Get a Podiatrist and see them often. I see the same guy year in, year out and if I get a cut or something I am right there at his door. Trim the nails, and check check check.