Implementing your estate plan requires the help of several people. Or perhaps one person who can take on various roles.
They can do things like authorize payments, or sign documents when you become unable. Typically you would set it up so they only get that authority if and when your poor health makes it necessary. They’d lose the power once you are well enough to do those tasks for yourself.
Their role begins the moment you die. Their main task is to distribute your estate per the wishes you set out in your estate plan. But they also need to do things such as inform creditors and perhaps take charge of funeral arrangements.
Once you find the right people to do these jobs for you, seek legal help to document your choices as part of your estate plan.