How to apply for Home Loan if agreement of Sale is misplaced/lost

Hi, My bro-in-law bought a flat in Mira Rd, directly from the builder and also completed the registration formalities. In a matter of few weeks post that, he misplaced his original agreement of sale. He has now taken a letter from the builder, made an affidavit and also lodged an FIR with the local police station. This helped him get a certified copy from the Registrar's office. We will now also put a notice in the news paper (Engligh & Marathi) through a lawyer. Can you suggest what else does he need to do to get a home loan from a bank for this property? He has a sanction letter from ICICI and hence we are talking to ICICI for the same. We are yet to hear from the branch, as they are awaiting a response from their lawyer. How does he progress with the loan? What else does he need to do to ensure that he may not face any issues in case he has to sell the place at a later point of time? Will the certified copy be considered good for any transaction in the future? Is there a way to have the flat re registered to secure an original sale of agreement? Thank you in advance for your help. Ashish