Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with a doctor.
Without the ability to examine and obtain a history, I can not tell you what the exact cause of the symptoms is. However I will try to provide you with some useful information.
It is odd though that he only has the problem here and not in India. From a neurological perspective, your boyfriend may have a disorder of the autonomic nervous system (i.e., the small nerves that innervate the sweat glands, etc). I agree that a dermatologist would be the most appropriate physician for him, and I would suggest that the dermatologist perform a punch biopsy to assess the nerves in the skin if they feel it may be neurological.
Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.
i forgot to add he is around 6 feet tall he is not over weight and is 22