Legal Question in Real Estate Law in Illinois

The authorities would probably tell you its a civil matter. If there is enough value in the car or in other estate assets, perhaps a well-worded letter from an attorney would help. Otherwise, your course is to proceed in court with probate. Does the boyfriend have any equitable arguments, such as he made the down payment and made or contributed to the payments even though it had to be titled in your sister's name?

If you have not filed to probate the matter, you can report the car stolen. Tell him you will report it stolen if he refuses to give the car to your family and if he does not give your family the car, then report the car stolen.