An act done by an attorney in fact under a durable power of attorney during a period of disability or incapacity of the principal has the same effect and inures to the benefit of and binds the principal and the principal's successors in interest as if the principal were competent and not disabled. Unless the instrument states a termination time, the power is exercisable notwithstanding the lapse of time since the execution of the instrument. A durable power of attorney that authorizes the agent to convey or otherwise exercise power over real estate does not need to contain the real estate's legal description.