I Have Extremely Dry Cracked Feet. I Have Tried Coconut

I have extremely dry cracked feet. I have tried coconut oil, dry skin lotions and creams but nothing helps. I do not have dry skin anywhere else. The callouses get so thick I gave to shave them or sand them down. This does not hurt since they are so thick and apparently the skin is dead. I am 53 yrs old and in excellent health. I take no medications other than vitamins. My dad had the same thing. I also have toenail fungus which I can't seem to get rid of. My feet are a mess! What can I do? I prefer natural remedies.