You can't disinherit in advance. But if and when either of them passes:1) You can refuse to serve as executor (if there is a will) or personal representative/administrator (if there is no will) of the estate, so you won't have to do anything with the estate, spend any time or money, etc. You CANNOT be forced to serve in these capacities or do/spend anything without your consent.2) If you do stand to inherit anything and believe it is more trouble, etc. than it is worth, you can "disclaim," or give up, the inheritance. If it comes to that, contact the probate court's clerk's office for instructions.