Succession certi / probate certi

I would like to know if one of family member (brother's son) file for succession /probate on the basis of 'will' (for younger sister who passed away 4 years back), and some other family members oppose it, and the 'will' is rejected by court, and case shows disposed . after that he again appealed in higher court for succession /probate certi. against my mother only. in this case if my mother wants to appeal for succession /probate as he already lost his case in civil district court, what should she does? she can file for succession/probate for herself only or if she gets certificate, benefits will be divided amongst all brothers and sisters. as other brother and sisters are not interested for any court case or to spend money for this. pl advice my mother can file in a court for herself only for succession/probate certi....can she get a sarkari vakil being senior citizen as she got sarkari vakil in high court. She needs succession or probate certificate to claim all benefits like pf , gratuity, other amount from company and also her property? pl advice. thank you in advacne.