IL subletter demands another month, no sublease

I live in Illinois and have been subletting the spare room in my 3BR apartment to someone for October. He moved in with the understanding that it would be October only with the potential of November subject to further discussion. On the 12th he verbally said he was interested in staying and I initially verbally said okay. My roommate was out of town till the 18th and when he got back he said okay. The subletter was never around until last week which is why we initially said okay. But ever since the 18th he's been very unpleasant to live with and for that and other reasons we emailed him on the 23rd to say that we were no longer interested in having him live here for November. He contents that my initial okay on the 12th was an immediate and binding oral lease and is demanding to and intends to stay through December 1st.

We never signed a sublease with him (both myself and my roommate are on the lease with the landlord). The only documentation that exists is the apartment posting which he responded to which explicitly says "October only", a deposit slip saying that we'll hold the room for an October stay (but gives no explicit termination date) and an email I sent reiterating our initial phone conversation prior to move-in that we discussed his stay would just be for October with November subject to discussion (he replied to this email and agreed). All he has is my initial verbal okay from the 12th.

All the meager documentation that exists supports that it was just for October. I live in Chicago Illinois; I can't find anything online in regards to subletter rights in Illinois. To me it seems that without a sublease he's essentially just a guest in my home whose paying for the privilege.

Can anyone point my in the direction of the proper Illinois housing code or even what the term for this situation would be? Informed advice welcome.

He is not just a guest in your home. He is a tenant as evidenced by the sublet posting. As such, he has all the rights of a tenant. If you have no written agreement with him, he is considered under the law as a month to month tenant. As such, you must give him the required notice to vacate as listed in your state law.

735 IL Comprehensive Statute 5/9-207 states that you may terminate a month to month tenant with a 30 day notice. Thus, you need to serve him a 30 day written notice immediately that he must be out of the unit and return the keys by November 30th. Hand it to him with a witness present, and keep a copy of the notice in a safe place where he cannot get to it (your car or at work). If he fails to leave by November 30, take the copy of the notice and go file to evict him.

Had you never mentioned a possible stay into November, he may have been considered a month to month tenant with a termination date. But since you put in writing in the email a possibility of a November stay and never gave him written notification that November would not be considered, you have opened the door for this possibility.