Your Aunt passed away and named your Grandmother as the beneficiary your grandmother preceded her in death and your mother is the executor of both of their estates and will does Mom get the money?

It depends on the provisions in the wills. If the wills name a contingent beneficiary then that person inherits if the primary beneficiary has predeceased the testator. If there is no contingent beneficiary then the property would pass as intestate property according to state laws of intestacy. You can check your state laws of intestacy at the related question link provided below. You should remember that a person becomes an executor only when appointed by a court. The probating of an estate should be supervised by an attorney who can answer all your legal questions and make certain the law is followed.