I am sorry for your loss. A small estate affidavit in Illinois applies to personal estate and the total must fall below $100,000. Further, there should not be any debt except for the funeral and burial expenses. Generally, banks and others holding estate assets will be cautious in these circumstances with three children and real property estate assets.
You should see a probate lawyer in this instance.
Good luck and God bless. I hope this helps you.
You may be able to use the Small Estate Affidavit process for the claim, which will be personal property. For the home, you may be able to work through an attorney and title company in lieu of probate. With respect to either, the facts would need to be explored with you. I would be pleased to speak with you by telephone. It is likely I am able to handle this in your area.