what to do about cracked heals?

My husband has really bad heals. If he does not sand them down with an eletric sander, they get to be an inch thick of this hard built up skin.

Recently he has been keeping them trimed down to almost where his 'real' heal actually starts, but now its cracked in his skin and pretty painful when he walks.

Does anyone have any suggestions on what we can do to help him. Tweet