Legal Question in Landlord & Tenant Law in Illinois

Your aunt is exposed to liability for failure to keep the common areas properly maintained. And if the renter's dwelling has building code violations that the renter didn't cause, to remedy them. Beyond that an owner-occupied 2-flat in Chicago is exempt from the Chicago Residential Landlord & Tenant Ordinance but is not exempt from general laws and building codes. She certainly should be carrying appropriate liability insurance, but the well-being of the renter per se is not her issue. She also is exempt from various other laws regarding accessibility, so she doesn't have to worry about putting in ramps or lifts. So the first things? Make sure she's adequately insured, and have a reputable home inspector give the place a thorough inspection for any code violations, and make sure if there are any that they are repaired promptly (this would be true whether or not the renter was disabled). Beyond that she owes no loyalty to a tenant who is on a month-to-month tenancy arrangement, but if the renter is good paying and otherwise is not a problem, your aunt may be better off with a known person than not. Plus, there are city agencies that could intercede both for the renter and against your aunt (Mayor's Office of Disabilities....), but a complete review of the situation would be required for that kind of determination.