Exemption under section 54F

Dear expert,
one of my client sold urban agriculture land as on 1st August 2019 for Rs. 28 lacs. The same land was registered in the name of both assessee and his mother and invested it in constructing additional floor for his existing residence as on 31st August 2020. This residential house is registered in his name only. Now my question is as follows
1. Is he entitled to claim exemption under section 54F? If yes then what extent?
2. Can his mother claim exemption under section 54F as she was the co-owner of sold agriculture land but not residential property?
Dear expert suggest me in this regard.