According to the Indian Succession Act, a standard, unprivileged Will needs to be attested by at least two witnesses (or more if you can). Each witness must either see the testator (the Will creator) sign the Will or at least receive an acknowledgement of the testator’s signature. The law also requires that these witnesses sign the Will in front of the testator. When it’s time to validate the Will in court, at least one witness has to be examined successfully, else the Will won’t hold up.
Recently, there was a similar case in the Punjab and Haryana High Court where the scribe (the person writing the Will) was also a witness to the Will. The high court had ruled that there is no legal provision which bars a scribe from becoming an attesting witness to a Will, provided the Scribe clearly states the intention to attest and become a witness to the Will.