My question involves workers compensation law for the state of: Illinois

My mom works at a hospital in Illinois. She slipped and fell on ice in a parking garage after leaving work. She was clocked out; however she did fall in the parking garage which she is instructed to park in by the hospital. Also, she was recently told that the parking garage isnt actually owned my the hospital itself. Anyway, she ended up breaking her ankle badly, requiring surgery and a lengthy recovery. Is this a workman's comp or disability situation? Is the hospital liable to hold her job for more than 12 weeks? She is worried about a lot of these issues and isnt sure how it will play out.