Interest deduction under sec 24b

My query is for interest deduction under sec24b & principal repay under 80C is legal ownership is required or loan should be in ur name.

For example Mr & Mrs A jointly owns a house property HOUSE1. Now they sell this house and purchase another HOUSE2. Full sale proceeds has been utilised for purchase of new house and moreover a loan has been taken by son of MrA i.e A junior but HOUSE2 is registered jointly in name of Mr & Mrs A for 54Deduction. Now my query is whether A junior will get benefit of 24b & 80C since loan is in his name but house property is not. Is legal ownership the criteria or person funding the transaction should get the deduction.

If possible share a case law relevant to this also.

Thanks in Advance.