Capital gain tax on release deed and subsequent sale deed - whether short term / long term

My grand father obtained a property by will. He passed away in 2016 leaving behind 5 legal heirs including my father. Now in 2021, 2 of the 5 legal heirs wish to release their rights in favour of my father by way of a 'release deed without consideration'. My father intends to sell his 3/5th share in the property immediately. I would like to get clarified on: 1. Whether capital gains tax or any tax at all would be applicable on the share of property obtained by way of a release deed by my father from his brothers? If yes, what would be the tax (long term or short term) and how it should be calculated?; 2. The capital gains that my father would make from the immediate sale of his 3/5th share in the property, will be taxed as long term capital gain or short term capital gain? Can the ownership of the previous owner can also be taken in the case of a release deed as well and could be interpreted to be within the terms of Section 49 (1) of the Income tax act? 3. Can a settlement deed be entered in this scenario instead of a release deed? If yes, what would be the tax implications upon sale by my father - whether long term or short term?