Undue clauses made in father's will

So my father has 4 sons (including me) he wrote this will in 1997 and was witnessed sign by my 2 married sister's husbands. The will is not hand written and note registered. It was typed by my eldest brothers son. I had not idea that my father wrote a will but he apparently knew all along, it was presented to me when my father passed away in 2013. At present the clauses in the will are very unfair and are at advantage to my eldest brother. The weird part is that even the executer of will (sister's husband) is unaware that there was a will. In the will there is a page missing which is basically the representation of house marking portions of all brother's space in house at the time 1997. The page is mentioned in the will as signed by my father, but the page is missing and my eldest brother says that it was never their. Now i have few things to ask, 1. I am really confused now that whether this will is even written by my father or it is forged by my eldest brother (personally i have seen him forging my fathers signature with ease in earlier days). 2. Whether a will with a missing page stands good in the court? (there were extension done to his portion by elder brother after 1997, which can be reflected only if we had that missing page showing original. 3. Is it fair that my brother's son typed the will for my father? I mean he is himself is a beneficiary and he himself drafting it raises suspicious in my mind of influence. Please help me with this.