Final answer:
The server should stop serving alcohol to the minor and contact a manager or security personnel, due to legal and safety concerns surrounding underage drinking.
Step-by-step explanation:
When a server is concerned about the number of drinks a minor has consumed, the server has a responsibility to ensure the safety of the patron, even if there are no visible signs of intoxication. In many places, serving alcohol to minors is illegal and comes with serious legal ramifications. The server should immediately stop serving alcohol to the individual and may need to contact a manager or security personnel to handle the situation appropriately. Additionally, in some jurisdictions, employees who serve alcohol are required to complete training on responsible alcohol service, which would provide guidance on how to handle such situations.