Legal Question in Real Estate Law in Illinois

Do not use self-help, such as changing the locks or tossing his belongings. This question is more complex than can be fully analyzed here.

To start, recognize that this is your mother's issue. So, she needs to be the one to initiate action unless there is a valid power of attorney or guardianship. You cannot take steps in your own name to evict.

To evict, unless he leaves voluntarily after your mother tells him he is no longer welcome, she will have to follow Illinois eviction law. An attorney will consider where this fits into the statute, but it is probably a five-day written notice, followed by the filing of the eviction lawsuit (referred to as Forcible Entry and Detainer). In your area, it is likely that a prompt court date can be scheduled.

The concern, will the actions involved endanger your mother or her property? So, as an alternative, you may wish to approach this more as a matter of elder abuse or press charges for other crimes so other authorities may step in. You can try the Illinois Attorney General's office, which has a section for elder abuse concerns. You can try local elder care organizations. You can try the police.