Signature forging

My brother and I owned a joint property - our Home. His name was registered in MHADA records and my neighbour while registering his wife's name in MHADAsubmitted documents which misrepresented that my brother is 'Secretary' of the society and someone signed the way he signs on the documents prepared on Society's letterhead like Extract of the SGM, Certified extract of the Resoultion passed in SGM, etc.(5 documents at least). Flat sale purchase agreement is done by my neighbour with say 'A' and the documents filed with MHADA states that flat is purchased from 'B' since MHADA list contains the name of 'B' and not 'A'. Even the wrong Affidavit has been filed with MHADA which states flat is purchased from 'B'. Time difference between Registration of Agreement and signing of Affidavit is only 15 days. This happened about 10 years ago. We learnt recently such irregularities from one RTI query and my brother reported to MHADA and police about the false documents and false signatures. Now when police started pre FIR (after a month of filing complaint), police called my neighbour and asked about the irregularities. My neighbour claims that he had received the society documents (signed) from the earlier Secretary (who is absconding). He further claims that the such events get time barred after 7 and half years of happening. Police has instead of preparing FIR asked us to get an order under CrPC 156(3) from the court. Now what I wish to know that what are the violations and what are the options for my brother to get justice and to prove his innocence?