Born and raised until I graduated college in Chicago. While the news has a lot about Chicago crime, if you follow the advice of visiting other big cities you will be fine.
I would stay downtown in the Loop or the Magnificent Mile. Not sure about hotel costs now but try looking at booking.com or last minute. There are always people downtown at night and unless you are partying until all hours, either an Uber/Cab or the CTA will be fine. Apart from NYC, Chicago has some of the best ethnic restaurants which are usually in the neighborhoods not downtown.Look on Yelp/Tripadvisor for some good ones.
Things to do-
Walk along the Lakefront for a while or just relax at Millennial Park, though The Bean is under repair.
The Art Institute has the finest Impressionist collection in the US.
Museum of Science and Industry to see the captured German U-Boat.
Not sure when you are going and whether your Mom likes baseball, but a Cubs game at the Friendly Confines of Wrigley Field is always a treat.