HUD home negotiating seller repairs

[Konstance C.]

Hi. I recently put an offer accepted on a duplex. It's a HUD home from Fannie Mae and I offered well over asking price. I am funding the deal through a 203k loan. But that was for minor repairs, new floors, upgrading the kitchens and appliances, mostly cosmetic things. Then two days ago, the inspection came back that the duplex had major issues. It needed all new wiring, new HVAC systems, new hot water heaters, etc. I want to ask Fannie Mae to fix the wiring, plumbing, and replace the HVAC and hot water heaters but my realtor said it's a "Hickman" (not sure if that's the correct word) law that says Fannie Mae legally cannot make repairs on the home and further more my counter would piss them off and they will cancel the whole contract and go with other offer. Is this true? What is the Hickman law? Can a seller just void an executed contract during the option period in the mist of negotiations? Has anyone had a bank make repairs on a HUD home before? Thank you for your help. My option period ends in four days.