Your son's calcium levels are obviously too high. It appears that the cause is being misdiagnosed. From the link, note the following information that seems to fit your son's situation.
"Here is the most important fact on this page: since vitamin D is required for humans to absorb calcium in their intestines, a low vitamin D cannot ever be the cause of high blood calcium. This fact is not debatable. Thus, if you have a low vitamin D and your calcium is above 10.0, then the high calcium in your blood must have come from somewhere else other than your diet (it came from your bones). Thus, if you have a low vitamin D, and a calcium level above 10.1, then you are almost guaranteed to have primary hyperparathyroidism and need surgery to remove the parathyroid tumor. A low vitamin D cannot ever be the cause of high blood calcium. "
Also, "The most common mistake we see from family doctors and endocrinologists regarding the diagnosis of primary hyperparathyroidism is that the low vitamin D confuses them and they think the patient has SECONDARY hyperparathyroidism. In other words, they think the low vitamin D was the CAUSE of the high blood calcium because the low vitamin D caused the parathyroid glands to become over-active. They then think that they can fix the high calcium by giving you high doses of vitamin D. We're here to tell you that there is no such thing as secondary hyperparathyroidism caused by low vitamin D that results in calcium levels above 10.1. No Such Thing."
"The body also wants to shut down calcium absorption from your intestines. It does this by limiting the amount of Vitamin D in your body. Thus, if your body determines that your calcium is too high... it can decrease the amount of calcium that is absorbed from your intestines by decreasing the amount of Vitamin D available. If your Vitamin D levels are decreased, you can't absorb so much calcium from your diet. This is a protective measure."
Teenagers normally have calcium between 10 - 10.7. Vitamin D needs to be higher.
Vitamin D Council has listed the amount you need daily to achieve certain vitamin D levels.
20 ng/ml 1000 IU
30 ng/ml 2200 IU
40 ng/ml 3600 IU
50 ng/ml 5300 IU
60 ng/ml 7400 IU
70 ng/ml 10100 IU
Okay Red_Star, thanks for the input.