Eviction of an unwanted family member

[Brie Schmidt]

Need some help with this one...

Grandfather owns a duplex, he is 90 and not in the best of health. He owns the duplex outright (in Evanston, a suburb of Chicago) and has 4 children, one of which has a power of attorney. T lives upstairs (not the POA child) and grandpa lives downstairs. T has been living there his entire life and has become destructive to the family. The other 3 children, including the one with the POA want Grandpa out of the toxic environment. They are going to move grandpa out and list the home for sale and the want T out of the house.

He has no lease, doesn't pay rent.... 

Can they just move his stuff outside and change the locks?  Call the police and remove him?  T has recently threatened violence on the family and they may be able to obtain a restraining order