If you can bring him inside where it is warm until her dries, I would try to do a shallow warm soak in Epsom salts or Dawn and water. Gently wash the feet off, so we can see a better picture of nis feet. Being a silkie, it can be hard to see the skin well because of feathers and gray skin. There may be scaly leg mites, dirty feet, or still could be some frostbite.