Hi, I'd like to help you with your problem.
It sounds like from what you said your mother possibly suffers from schizophrenia. This is a very difficult condition to cope with, particularly for family members. I sympathize with your situation.
First of all, you are not responsible for your mother. That is not to say you cannot have a strong desire to help her. But taking on this burden can be extremely stressful, especially if you take it on alone. Support is a very important component to helping you cope. One way is to contact NAMI- The National Alliance for Mental Illness. They are at http://www.nami.org/
I agree with you about the Illinois commitment law. They may allow your mother to be committed, but only if she is deteriorating. From what you said, it sounds like your mother is stable at this point. If you should see her becoming worse, such as her hygiene declines, she is not eating or otherwise not caring for herself, I would attempt to bring her to the ER for an evaluation. You may also call a local mental health center and see if they agree that she meets the criteria for admission to a MH facility. They can offer you options for dealing with the situation.
Surviving Schizophrenia: A Manual for Families, Patients, and Providers by E. Fuller Torrey is a good book to get to help guide you through this. You can find it on Amazon.com or your local bookseller may be able to order it for you.
Most of all, remember to care for yourself. Take time to have fun, get away from the situation for a while and build a support system for yourself to fall back on if needed.
I hope this helped,