Hi, Cheryl
my husband hit some of the cracking at the end of his chemo, and it is a distressing side effect. My husband found the Eucerin Aquaphor ointment to be soothing; if it helps Doug, you can get it in a fairly large jar. I am sure you are already doing laundry with fragrance-free detergent to avoid any additional aggravation of his feet. You might look at diabetic socks; you can get some that are padded and not constricting.
Besides the pain and annoyance these fissures cause, we in the developed world are just not used to dealing with these skin issues, and I think this makes it harder to deal with emotionally for us. When my father had terrible edema from congestive heart failure, I have to attend to his legs, and then move on - if I looked at them, it made it harder for both of us. Putting a good CD on helps. Distraction can be a good thing.
The other thing that occurs to me, remembering my dad, is maybe speaking with a wound-specialist nurse. His nurse was able to greatly improve his comfort level and quality of life.
Best wishes and hope you both can find some relief.
Maria