My grandfather-in-law (80 year old) has an HUF account in which he is the Karta and his wife and daughter-in-law are the only other members (his son passed away last year). In case something were to happen to him, who can now become the Karta of this HUF? I want to be prepared for this eventuality in advance and take actions now in case this creates complications later. Can you please advice on who can become the Karta after him? Also, what sort of documentation would be required in advance for this?