Final answer:
Gary Parks' symptoms of excessive thirst may indicate diabetes mellitus, and it's important for him to seek a medical evaluation.
Step-by-step explanation:
The correct medical term to describe Gary Parks' condition of excessive thirst, especially between 2 and 4 am, and a family history of type 2 diabetes, is likely diabetes mellitus. Symptoms of untreated high blood glucose, which characterize diabetes, include frequent urination, increased thirst, and increased hunger. Given Gary's symptoms and family history, it is important for him to consult a healthcare professional for proper diagnosis and treatment. Polydipsia refers to excessive thirst and is often a symptom of diabetes. In Gary's case, his excessive thirst, especially during specific hours in the night, could be an indication of type 2 diabetes. This is further supported by his family history of type 2 diabetes.