This is my response to youL
1.Firstly the loan will have to be cleared to transfer to your name;
2. Or change the applicant's name to your name so that the loan amount is drawn from your account;
3. Till the time loan is not cleared or transferred in your name till then you do not become the owner;
4. Also your father and sister will have to execute a Gift Deed in your favour;
5. You will have to execute and register the same;
6. Consult a local lawyer for informed opinion and take legal steps.