Transmission Under Maharashtra Co-operative Socities Act, 1960

My father-in-law expired in 2019. My mother-in-law was his sole Nominee in the Society's records and is also the sole beneficiary under his Will. There is NO claim/dispute regarding the Will or flat by any person. She filed all the required forms/documents, including Will, Indemnity, etc. with the Society to admit her as a member. Their only child, my wife, filed an affidavit with the Society accepting the Nomination and Will. The Managing Committee admitted her as a "nominee member" and is insisting for no specific reason that the Will should be probated. Is she not entitled to be admitted as a regular member under section 154B-13 and / or the first proviso thereto of The Maharashtra Cooperative Societies Act which do NOT mention that the Will or testamentary document is to be Probated? Further, even section 213 of The Indian Succession Act requires a Will to be probated ONLY where the right of the legatee is to be established in a Court and NOT otherwise/automatically.