thanks for using Health Care magic .
I would be pleased to answer your question
I can understand how worried you might be . I would suggest that you should take him to the Dermatologist
. The Dermatologist will examine the are under the UV light / Woods lam. Vitiligo
is the prime concern and should be ruled out . The second cause could be a simple post inflammatory hypopigmentation
I suggest you should take him to the Dermatologist .
Thanks and Take care