Duplex seller issue

[Brad Ickes]

I am in negotiations on a duplex in my town currently. I have offered 95000 on this with the asking price of 114000. This offer was accepted contingent on a home inspection. The home inspection is now back and I have found from it items which total to around 6000. I am asking the seller for credit towards anything safety, structural, or code related so I am only asking for 4000 of that and him to reduce sale price to 91000. These items include a rotten sill plate in the garage, gfi's throughout the house where needed and a small amount of knob and tube. In addition badly corroded valves for the heating system and replacing the PVC vent pipes coming out of the fuel tanks to fireproof material. He responded to this that he does not feel these are his responsibility to fix and feels as though the 2300 that he put into fuel recently should be a concession towards this. Keep in mind we do not close until the end of March so they are burning through this as we speak. Also we are planning on ripping the oil furnace out and putting in a high efficiency gas so I feel as though I should play hard ball and tell him to take his fuel which legally he can do before closing, if that is the case the PVC vents could go away however that's only worth 200. What's everybody's thoughts on this deal. This place has been on the market for over 500 days and this is a cash deal. If he loses this deal he now has to disclose these items.