Numerous times a seller hides defects or misrepresents the condition of the property to the seller. You as a buyer have rights in Illinois. You can sue the seller for recission–or in other words cancel the contract and get your money back and let the seller have the headaches of fixing the property. Recission is warranted where the seller misrepresented the condition of the house or where both the buyer and seller did not know of a major defect in the house such as it being termite infested. Then a Judge may order the deal recinded and you will obtain your purchase money back and pay the seller reasonable rent while you resided in the property.
If you wish to keep the property, then you can sue the seller to fix the house to the condition he represented it to be in at the time of the sale. Thus the seller will have to pay for the costs of repairs.
In Residential Disclosure cases, if you can demonstrate that the seller knew of the defect and did not disclose it to you, and you sue the seller promptly–within one year–you can obtain the costs of repairs and your attorneys fees back from the Seller.