Did he agree to on the REPLY TO INSPECTiONS form?
If he did, then he needs to fix this or the title company can hold money back until this is fixed.
You do not have to proceed with the sale if he has promised it to be done and now won't do it.
Is he saying now that we will not do this? Do you have an attorney or an agent?
Whenever you respond to an inspection report to get things fixed, you must always enclose what will happen if the repairs are not done. For instance, that if this and that isn't fixed, then the seller must credit the buyer x amount of dollars for the buyer to fix the repairs. Something along those lines.
You always need to cover your assets when dealing with a sale/purchase this large.
Terrence Charest, e-Pro