Forgery

F - Female M-Male A married female 'F1' has acquired X acres of dry land in 1970. She has developed the land by planting coconut trees along with his husband 'M1'. F1 and M1 had only son M2 who married F2 and they had only daughter F3. In the year 1990 F1 & in 1994 M1were died without making any will. F3 married M3 two years before demise of F1. M1 & F1 were arranged this marriage and has given huge amount of dowry. For the purpose of this the sold out Y1 acres of land. M3 had lost all his property for his luxurious life and also left with huge debits. F3 approached M2 for help. M2 sold out Y2 acres of land to P1 and given that amount to M3. P1 has asked to execute sale deed by M2 and F3 together even though F3 had no rights, the deed was executed as per this wish of P1. Now M3 had collided with a 3rd person (from whom he lends the money) and created an agreement of sale for entire land (X-Y1-Y2). F3 signed this agreement. M2's sign has been forged. Pls note this agreement was created on Rs.100 stamp papers with 10% of mrkt value of land and was not registered. 3rd person has sent a lawyer notice to M2 asking to execute sale deed as per the agreement. Some how F3 has managed M2 without reading the notice. Now 3rd person has filed a case in the court to direct M2 and F3 to execute the sale deed. M2 has not entered into any agreement and he has difficulty to move and old enough. My questions are ..... 1. How much time does it take to prove it as a forged document. 2. What suggestion you give to M2 to save his land 3. Does F3 has any rights on this land