How would the heir find someone to help them? How would the original owner who is bit coin savvy find independent help to add instruction to a will. Are their independent consultants? To this point I have not run across any financial planner who has yet educated themselves on bitcoin.
The original owner can make a video will. How nice is it to see your loved one explain on film how you can reclaim a large amount of money?
Anybody can be an independent consultant. You need to find someone who you can trust enough not to betray you. If the consultant takes your bitcoins he most likely gets away with it as you prove he took them.