Final answer:
The minimum age of a substitute decision maker who is not the parent of the patient is 25 years.
Step-by-step explanation:
The minimum age of a substitute decision maker who is not the parent of the patient is 25 years.
Parents can provide consent on behalf of their children, but children are not competent to provide consent for themselves. Therefore, a substitute decision maker is needed when a parent is not available or unable to make decisions for the patient.
In this case, the minimum age required for a substitute decision maker who is not the parent of the patient is 25 years.