If an executor or trustee is not following the terms of a will or trust, that person needs to be put on notice that it is not acceptable. You need to hire your own attorney (which, certainly if you prevail, could be paid for my trust funds) to approach the trustee (or sue them) to get what you are entitled to. If the the estate is in CA you probably need a CA attorney.
This is not legal advice nor intended to create an attorney-client relationship. The information provided here is informational in nature only. This attorney may not be licensed in the jurisdiction which you have a question about so the answer could be only general in nature. Visit Steve Zelinger's website: http://www.stevenzelinger.com/
A trustee (trust) or executor (will) has a legal obligation to follow the provisions of the trust or will. However, if the funds in the estate have been exhausted prior to paying for your schooling and there was not any misconduct on your mother's part, then there is really nothing you can do about it. Any provision in a trust or will is limited by the amount of funds available in the estate. I agree with my colleague that you should hire an attorney to ensure your rights as a beneficiary of the estate are protected.
My responses are of a general nature and not having the opportunity to get all of the background may mean that they are not complete. I may not be a licensed attorney in the jurisdiction where you are seeking advice and is based solely on the laws and my expertise in those states in which I am licensed. Therefore, this advice can provide a good foundation in seeking quality legal advice in your particular area.
Assuming that your mother is the executor, she is bound to follow the provisions of your grandmother's will. If she does not do so, you have a right to hire an attorney and question whether your mother is following the terms and the provisions of the will. If she is not, she might be ordered to reimburse the estate and could possibly be removed as executor. On the other hand, if there are insufficient funds in the estate to accomplish what your grandmother wished, there is nothing that your mother has done wrong. A good probate or estate attorney will know what needs to be done.
NOTE: If your grandmother's estate is in California, you will need a California attorney.
If grandma died in CA then that's where the "primary" probate of her estate would occur. You may need a California attorney because the "primary" probate would be where grandma passed away. If she had assets in Illinois also requiring probate, then an "ancillary" probate may be required here. If mom is the executor of the will, both states require a minimum level of accounting of estate receipts and disbursements and the federal and state governments require estate tax returns that should reveal its economic situation. But as others have stated, at the "end of the day" if grandma only had so much in her estate and those funds are gone, there's nothing your mom can do.