Your answer lies within the terms of the Trust itself, and you should seriously consider taking the Trust document and your concerns to an attorney. The Trust's terms might be written in any of a variety of ways, and the terms should evidence the intent of the person(s) that made the Trust to begin with.
Does the Trust document include any provision about occupancy? Is this live-in arrangement the product of the Trust's terms or simply a product of one beneficiary taking advantage of another? Does the Trust document discuss the items that concern you, including the mortgage, taxes and expenses of upkeep?
If the Trust truly distributes the property in equal shares, then the beneficiaries should be equally liable for the expenses that come along with the property. Nobody benefits from a vacant house, but if one beneficiary is receiving a premium by virtue of occupying the house as well, then certainly that benefit should be taken into consideration when allocating the expenses. You'd be well-served to take your concerns to an attorney near you in order to fully appreciate the situation that you find yourself in.
This answer does not constitute legal advice. I am admitted to practice law in the State of Texas only, and make no attempt to opine on matters of law that are not relevant to Texas. This answer is based on general principles of law that may or may not relate to your specific situation, and is for promotional purposes only. You should never rely on this answer alone and nothing in these communications creates an attorney-client relationship.
That is a very complete answer from my colleague. There is no special law in IL that would require you to pay expenses in this situation while another reaps the benefits. The trust might be unusual enough to do that, but even then perhaps you could get a reverse mortgage to cover that. More likely is that your are being deceived, and need to see an trust law attorney.
So far, this is free to you. Until you pay a fee, I am not your lawyer and you are not my client, so you take any free advice at your sole risk. I am licensed in IL, MO, TX and am a Reg. Pat. Atty. so advice in any other jurisdiction is general advice and should be confirmed with an attorney licensed in that jurisdiction.
I very much enjoyed reading the other attorneys answers - they are both very good!
Bottom line is that you need to consult with an attorney so that you understand what the terms of the trust and what rights you have against the co-beneficiary. This situation, unfortunately, is not uncommon and when real estate is owned in a land trust or revocable trust this can be a big problem.
Take a look at naela.org for an estate planning attorney in your area. Good Luck!
Legal Disclaimer: Paul A. Smolinski is licensed to practice law in the State of Illinois only, and as such, his answers to AVVO inquiries are based on his understanding of Illinois law only. His answers are for general information about perceived legal issues within this question only and no response to any posted inquiry should be deemed to extend any right of confidentiality between you and Mr. Smolinski, to constitute legal advice, or create an attorney/client or other contractual relationship. An attorney/client relationship is formed only by specific agreement including an evaluation of the specific legal problem and review of all the facts and documents at issue. We try to insure the accuracy of this information, but we cannot guarantee its accuracy. The reader should never assume that this information applies to his or her specific situation or constitutes legal advice. Therefore, please consult competent counsel that practices in the subject area in your jurisdiction and who is familiar with your specific facts and all of the circumstances.