Hypergranulation can come from a couple things, including infection, too many proteases in the wound bed(pretty common with chronic wounds), etc. Silver nitrate will temporarily take care of the problem but not correct the cause. Also, the callous surrounding the wound is likely not helping the epithelial tissue migrate across the wound bed. Can he see a podiatrist and have the callous debrided if he can't make it to a wound center? I would use a product with a protease inhibitor if you can afford to (a collagen like promogran or prisma). Can the doc give you an order to do a tissue culture and send it to lab to see if it's infected? Not sure about HH rules, etc. Just curious, is this a diabetic foot ulcer or an ischemic ulcer?