This is the detail families miss most often. A power of attorney set up years earlier for banking convenience may not survive the very event, incapacity, that it now needs to cover, which is why the Law Society of Saskatchewan recommends confirming the document's wording before relying on it in a health crisis rather than after.
Once death has occurred, selling the house runs through the estate process instead, with the executor or administrator signing rather than the person who previously held power of attorney, and a lawyer needs to confirm that authority through probate or letters of administration before a sale can proceed.
Reviewing this while the person is still capable, rather than during a crisis, is the $800 to $1,500 in legal fees that saves real delay later. Get your hand-reviewed valuation from Joel Dyck.