My name isXXXXX have been a licensed attorney for over ten years and will be assisting you today.
Because she has no will, the rules of intestate
succession in Illinois take over.
According to those rules, if a person dies who is unmarried, has no children or living parents, then the entire estate
passes to the living siblings in equal parts. If you are the only sibling, her entire estate would go to you.
That said, you are not legally "responsible" for anything. The law does not say you are the one who has to probate
her estate because you are her closest living relative.
Assuming she has an estate worth probating (and it sounds as though it is valuable enough that it is), someone in the state of Illinois is going to have to open the probate proceedings.
You mention that you do not have the money to hire a lawyer. You may not have to hire one out of pocket. If there is value in the estate, many estate lawyers will work for a fee based on the size of the estate or promise to be paid by the estate. As that is the case, I suggest you do consult with a lawyer in the county where she lived to discuss probate options.
If you have more questions please feel free to ask. I'll be happy to answer them. If you do not, please do remember to rate my service in assistance to you today.