Doubt in cancelling will

Will can be cancelled during the life time of the testator. He is not feeling well. his hands and legs are not  working, no problem,  if he can perceived by his senses  that he is canceling the will, the will, will  be cancell. 

Law of will is very clear. A person must be having sound and disposing mind at the time of making his/her will and he can change it as per his own wish subject to aforementioned condition. Secondly, Will has to be attested by atleast two witnesses signing in presence of Testator and each other and also Testator must have signed in presence of two witnesses. If your Uncle is having sound and disposing mind then he can change his will otherwise cloud will be there regarding validity of new Will. If he is having sound and disposing mind but due to some health issues his hands are not working then you can register it by requesting concerned Sub Registrar office to arrange registration at home by taking his thumb impression. Attesting Witnesses are most important factor in Will comes into the picture only when Testator is not alive. So role of witnesses are outmost important.   

Thank you sir