Hello.
Thank you for asking at HCM.
I went through your uncle's history.
In fact, there are so many causes of itching. Finding out right cause requires a detailed questioning and examination, also sometimes some investigations.
However, from your current history, I would suggest you following:
1. If your uncle has itching with urticaria/hives/
skin rash, I would suggest him 
levocetirizine and 
montelukast daily for at least 1-2 weeks.
2. If he has only itching, without any skin lesion, I would first think of dry skin and suggest him moisturizer application along with 
multivitamin and 
vitamin E supplements.
3. If he is diabetic, please make sure his sugar is under control.
4. If he has any other disease or he is taking any regular medicines, it is important to decide whether that disease or medicine is causing itching.
5. If above measures do not help, detailed investigations will help.
Hope this will be helpful to you.
Wish your uncle a quick recovery and the best of the health.
Should you have any query, please feel free to ask at HCM.
Regards.