Dear Sir,
Hope you are doing well !!
-There would be no tax liability on you for purchase of property.
-However, your father will be required to pay the capital gain taxes on sales.
-Amount of capital gain would depend upon sale price, sale date, purchase price and purchase date etc.
-When an individual sells a property and buys another residential property, he will be eligible for exemption under Section 54/54F subject to conditions.
It is advisable to take a phone consultation for detailed discussion.