South African common law determines that a power of attorney terminates once the principal becomes mentally incapacitated. In other words, when a principal is no longer able to perform the act in question himself, the agent can no longer do it for him.
A General Power of Attorney lasts until is it revoked or until you lose mental capacity or die. Unless there is a limitation on an Enduring Power of Attorney it continues until it is revoked or by death of the Donor.
A Lasting Power of Attorney only remains valid during the lifetime of the person who made it (called the 'donor'). After the donor dies, the Lasting Power of Attorney will end.
What happens when the donor of an LPA dies? The power granted by their LPA, or LPAs, automatically ceases. This means that if you have been acting as an Attorney under that LPA, you will no longer have the authority to manage the late donor's affairs.