Hyperparathyroidism Support Group
Hyperparathyroidism is overactivity of the parathyroid glands resulting in excess production of parathyroid hormone (PTH). Increased PTH consequently leads to increased serum calcium (hypercalcemia) due to 1) increased bone resorption, allowing flow of calcium from bone to blood, 2) reduces renal clearance of calcium, and 3) increases intestinal calcium absorption.
It sounds like your son needs to have testing for primary hyperparathyroidism (PHPT). Yes, it's always indicated when there is a high calcium because parathryoid glands control blood calcium levels. The primary care provider can check: parathryoid hormone (PTH), serum calcium, (ionized calcium is good to check too because it shows the calcium that's bio-available and it may be higher, e.g., at higher risk for stroke, than serum calcium indicates) and vitamin D, as these all correlate.
Generally, a primary care provider will not refer to an endocrinologist until it's clear there's an endocrinology issue (and yes as you may know, PHPT is one).
I hope that helps!
Peace and blessings to you and your wonderful son,
ASpell