He needs to take 10,000 IU Daily of Vitamin D3 with the goal of getting his blood level to 60-70 ng/ml after 3 months. This is essential for diabetics.
* 10,000 IU D3 Gelcaps Daily to achieve correct blood level in most people
-Proper 25(OH)D Blood Level is 60-70 ng/ml Toxicity overdose > 120-130 ng/ml
See section 19.8 in my research report for more on Vitamin D3.