Not having any ground fault protection.
Dont have my code book handy to quote a section but I know 210 has something in there about "anytime you work on an old two wire system GFI protection is required." When extending a circuit on a two wire system I change the receptacle I tap off of to a a GFI then I change the breaker to an arc fault. This is enforced by the inspectors. Since he is not extending any circuits, to me that would mean he would only need gfi protection
The requirement to add a GFI to a two wire system is only in order to change to 3 wire receptacles. Adding in line fuses doesn't have a thing in the world to do with that code.