The cash IS in the will even if not specified, it was still his “belongings”. Also, a senile person cannot change a beneficiary—they don’t have the requisite capacity to do so. Therefore, the change of beneficiary is not effective. Get yourself a lawyer, ASAP. The evidence of sexual crimes is another matter—go to the police. You need to act fast on this will issue before the money can’t be traced. Also, the insurance company needs to be notified right away that the change in beneficiary is being challenged before they pay him the money. Get going!