1. for the bank accounts with operation mode 'Anyone or Survivor', upon demise of your parent, the money will come to you exclusively
2. for the nomination made by your mom for the PPF Account, after her demise, you will get the money only as a trustee and you will be liable to share that money in equal proportion with your sister. A nominee does not automatically become entitled to the monies of the deceased account holder but holds that money in trust for the legal heirs of the deceased account holder
3. if the bank accounts were made joint account with you at a time when your mother had lost her memory, then it cannot be said that she willingly agreed for making the account as joint with you. When she was in loss of memory, she becomes incapable of contracting and any signature given by her at a time when her memory was not sound then it is not binding on your sister and your sister would get a share in the moneys lying in the bank accounts. However your sister has to first prove that your mom's signature was taken at a time when she had lost her memory
4. cash gifts made by parents during their lifetime are solely the prerogative of the parents and they can gift the cash to any person of their choice. Cash gifts made to you in their lifetime becomes your sole property and your sister cannot claim in the same after your parents demise