My father had DC so severly on one hand that his fingers were completely curled. Many years ago a hand surgeon fixed it by slicing the cord in a criss-cross fashion. A huge bandage and many months of PT followed. His other hand is also affected by DC, but it is minor. My brother has the DC cord tightening and unmistakeable bumpiness on one hand, though it does not yet require repair. There is certainly a genetic/heredity aspect to DC.
I think some cases can ce cured by botox injections directly into the thickened area.
Best wishes to your husband for a speedy recovery