Tax implications on a Sale of a Joint Property with GPA

Myself and my sibling hold a joint property in Bangalore in our names. My sibling is currently not in India and may not be in India while selling our joint property hence has made a registered GPA (for sale) appointing me as a lawful attorney. The GPA allows me to receive my sibling's 50% share of sale proceeds too, in my name. We both wish to gift the entire sale proceeds immediately to our mother for her expenses. We have a prospective buyer who be will be taking a home loan from a private housing finance company. My question is 1) Is is alright to receive the entire sale proceeds in my name including my sibling's 50% share as the GPA allows? 2) What are the tax implications that I will have? Am I allowed to pay the capital gain tax only for my 50% share? Or should I bear the entire capital gain tax since I may be receiving the entire sale proceeds in my name? 3) Should we both siblings prepare a gift deed before gifting the sale amount to our mother? Or can the gift deed be made after the transferring the money to our mother's name?