Purchase Contracts: Can a Buyer be Compelled to Go Through With a Real Estate Purchase

My question involves real estate located in the State of: Illinois
My neice and her bf are looking to buy a home. They foolishly jumped in too quick and signed an offer without consulting anyone. Their realtor is related to the sellers realtor. The federal loan inspector said no knob and tube wiring. Seller wants to have a contractor patch new to the knob and tube inside the walls to save money. Neice doesn't think this is appropriate. Realtor harrassing and showing up at her work and seller threatening to sue. Neice and bf signed offer contingent on electrical being redone, but it doesn't spell out the stipulation about knob and tube--that was a lender thing. Realtor claims if they can get any electrician to certify it's safe, they are required to buy. The realtor told the kids' parents Sunday that they were not required to buy. Now she's threatening them.

This whole thing has been a mess. Can they be sued or forced to buy?

Purchase Contracts: Can a Buyer be Compelled to Go Through With a Real Estate Purchase