1. he shall have to either convey the title of the property now by executing and registering a gift/settlement deed before the Registrar at Kolkata or execute a will sitting at Mumbail bequeathing his properties to you after his demise.
2. Since he is in a terminal stage of his life and is unable to appear before the Registrar at Kolkata, he can execute and Registrar a POA in favour oif yourself or any other person authorising the said POA holder to register a gift deed in your favour.
3. The said POA can be registered in Mumbai by commissioning the said registration (i.e. by calling the registrar to his bed for taking his signature and thumb impression for completing the registration of the POA executed by him).
4. Based on the said POA, its holder can register the gift deed in your favour duly conveying the title of his house in Kolkata in your favour.