Partition Suit Filed after 18Years of Testator Death

Plaintiffs filed a Partition Suit against Defendant1 and Defendant2 after 18Years of death of Father of all Plaintiffs and all Defendants, Defendant1 filed a Declaration Suit based on an Unregistered Will,Defendant2 already left the Property and never contesting the Suit, Plaintiff4 on behalf of all Plaintiffs opposed the Will,Plaintiff4 stated that he may Challange the Unregistered Will Whenever Defendant1 present the Will in the Court,After Seven Years of Partition Suit Defendant1 filed Certified Copy of Unregistered Will alongwith an Affadavit of one Attesting Witness(Paltu Singh) of Will in support of the Unregistered Will(already filed in Probate Suit),But Plaintiff4 on behalf of all Plaintiffs state that it is a forged Will and the Signatures of the testator are forged and both the Attesting Witness are Unknown to the testator,After 2Years of filing of Certified Copy of Affadavit of Attesting Witness of Will,Plaintiff4 on behalf of all Plaintiffs amended the Plaint to challange the Will (saying that it is very difficult to Challange the Will in Probate Suit),But Plaintiff4 on behalf of all plaintiff could not Challange the Will in Partition Suit and also could not Challange the Will in Probate Suit In last 6Years,Plaintiff4 on behalf of all Plaintiffs also could not provide any evidence to challange the Will after amendment in Partition Suit,Now legal heirs of the Defendant1 contesting the Suit. Facts:- (1) My Grandfather(testator) Executed his Will on 22nd August,1994. (2) Defendant1 filed a Declaration(Counter Claim) Suit Based on Unregistered Will in 2013. (3) Plaintiff4 on behalf of all Plaintiffs Could not Challanged the Will in last 30Years after testator died. (4) Defendant1 filed a Probate Suit in October,2018 along With an Affadavit of one Attesting Witness(Paltu Singh) Stating that Will was executed in presence of both attesting Witness. (5) My Grandfather(testator) and my father(Defendant1) Jointly purchased this Property 60Years ago and also in possession from last 60Years. (7) One Attesting Witness of the Will Prakash Chand Died on 2nd March, 2015 and the Second Attesting Witness of the Will Paltu Singh died on 17th November,2019 . (9) Paltu Singh(Attesting Witness) of the Will has submitted his affadavit mentioned that the testator had Signatures on the Will in the presence of both the attesting Witness and during that time the health of the testator was fine(sound) in Probate Suit. (10)My Grandfather(testator) died on 28th Februry,1995. (12) During Cross-Examination Plaintiff4 stated that he do not know When the Property Purchased,First stated that testator did not executed the Will then said that testator executed the Will but that was incomplete than said testator did not execute any Will legaly, Plaintiff4 came to know about the Will in 2018 but Plaintiff4 did not Challange the Will nor filed any Suit in the Court to cancil the Will Plaintiffs did not file any FIR in the Police against Will,but in future they may Challange the Will. (14) Probate Suit is pending. (16) Plaintiff4 accept in Probate Suit that Will came to his knowledge on 08-01-2014. (19) Both the Attesting Witness died(During Trial),Legal heir of Defendant submitted their death certificates in the Court. (20) Defendant1 never appeared in the Court as defendant1 was suffering with Cancer from 4Years before from his death. (21) Plaintiff4 himself accept during Cross-Examinations that Defendant1 is in Possession of the Property from day one, Plaintiff4 had came in the Disputed property after 25Years of its purchased,Plaintiff4 also accept that Plaintiffs never Challanged the Will never filed FIR against Will never Filed any Suit in the Court to cancil the Will. (21) Plaintiff1,Plaintiff2, Plaintiff3 and Defendant2 never appeared in the Court. (23) Plaintiff1 filed Chief for Cross Examination but never appeared in the Court. (25) Plaintiff3 already left the Property 12Years before filing of Suit. (26) Plaintiff1 left the Property after 4Years of filing the Suit and died in 2021. (27) Legal heir of the Defendant1 did mistake in Cross-Examination because Advocate of the Plaintiff asked the Question very cleverly and Legal heir of Defendant stated that I do not know the documents I filed and I do not know the numbers of room in the property. (28) Plaintiff4 is also in a small part of Possession. (29) Plaintiff4 also request in 2018 Probate to stop the decesion of Probate under section 10 of CPC till the Partion Suit decide as the Subject Matter of both the Cases is same (30) Argument Pending. Question:- How Plaintiffs can win the case ?