Owner occupied Chicago multifamily, tenant not paying

[Prabin A.]

I have a multi-family owner-occupied building (3 unit). The tenant is refusing to pay the July rent, and his move out date is the end of this July. His lease has already expired, and he is on a month to month basis. He has a friend living in the unit instead of himself. I used the CAR lease when I signed with him. I read in the CRLTO that it doesn't apply to the owner-occupied 2-4unit building. I am worried he will extend without stay and cause a further issue. What should I do?