WILL, Partition Suit, Ownership, Probate.

(Very Confidential & Anonymously posted). This is a property case of three deceased brothers - A (eldest), B (middle) & C (youngest). B-1 is Plaintiff one of the sons of B & C-1 is Def. 1A myself son of C. A purchased a property from his self-acquired funds many years ago in his sole name as per Lease Deed, he died a widower without issues. Three brothers, their families lived in this building in separate flats and are still living in it. In '70's, B's flat was sold and he moved in A's flat with his family. During this tenure, A and C had jointly done business, but B was kept out of it doing only petty work for their business. In early '80s, A was forced by B & B-1 to make Will in which he declared the bldg is owned by A, B & C jointly and he gives his flat and his 1/3rd share to his nephew B-1. My father C was kept in dark as he would have opposed it. Probate Petition was filed by B-1 in Bombay H.C in '80s, against citation, my father C filed Caveat, thus it became a suit. Later during '80s, B-1 also filed Partition Suit due to growing disputes between two families. B-1 never co-operated with my father C in jointly collecting rents from tenants, paying BMC taxes, etc in spite of Consent Terms for joint management of property. So H.C appointed Court Receiver. After many years off & on in this Case, to my surprise, Bombay H.C recently granted Probate to B-1. Though full cross-exam was done in presence of High Court appointed Commissioner, Judge considered only Probate related Q's & A's, nothing else about other facts and details. Back to the roots, as per Land Record and Sub-registrar's record, property is in the name of 'A'. However, A had mortgaged this property to a Trust in '60s to borrow money and in that Trust Deed made by a Solicitor, names of B & C were added without any Sale / Purchase or any other Deeds. (I still fail to understand why these two names were added.) Two years later, A repaid money to Trust and Trust cancelled Mortgage Deed, returned property to A, B & C through a Deed. Few years ago, B-1 submitted Property Card in Courts which shows A, B & C as owners. B-1 insists P.C. is a legal document - obviously! My contention is by adding names in mortgage deed will not make them co-owners, ownership can not change without proper agreements between parties and also Property Card is only for fiscal Revenue and tax purpose, not a Title Document. So P.C. is not a proof of ownership. Now that Partition Suit is due in City Civil Court where we had already questioned ownership claimed by B-1 and demanded supporting Deeds in reply to Suit and in Written Statement. In spite of many years gap, B-1 has not replied to Q's asked by us and somehow or the other avoiding it. B-1 has already claimed even before grant of Probate his 1/3rd share (of A) and B's 1/3rd share while filing Partition Suit. Now with above scenario, what should be done by us in Partition Suit to prevent B-1 from taking undue advantage and usurping 2/3rd property which is absolutely illegal and under fraudulent documents and circumstances and purely a case of fraud? Expert opinions and guidance shall be highly appreciated. With regards, Anonymous.