Bank settlement for legal heir

1 year ago

My brother deceased last year, he married twice. First marriage got divorced, has daughter (age 18).
Second marriage, wife died 3 years back, has step son (age 18).

My brother has savings account in a small finance bank, and had given his step son as Nominee, with relationship as "Son".

When Step son approached bank, because in bank record it is declared as "Son" and step son AADHAR doesn't have my brother name as father, Bank denied settling account to Nominee.

My mother and brother's daughter are the legal heirs for my brother, we have govt. legal hier.
When legal heirs approached bank to close account and settle the balance, their legal team is asking us to get High Court Order.

I heard High Court Order process is long and expensive (7.5% of total amount in bank should be paid + lawyer and other fees).
My mother need this money for her medical expenses and brother's daughter need this money for studies and marriage expenses.
They cannot afford hefty amount for the High Court order expenses. Please advice any other better option.