Inheritance in joint-property in co-operative society (gala)

A person jointly (his deceased wife being co-owner) owns a gala (office space) in a commercial plaza registered under Maharashtra Co-Operative Societies Act, 1960. Co-owner was a Hindu woman, died intestate. The society has not yet issued any share-certificate nor conveyance done by the Builder, although Co-operative society formed in the year 2014. Couple has one son out of wedlock. The query is as follows:

1. Can husband inherit the remaining 50% of ownership of his deceased wife ?

2. In case son wants to inherit the 50% of his mother's ownership in the Shop. What procedure he needs to follow in absence of any share certificate ?

3. Is any stamp duty required to be paid to the State Govt. by the Husband or Son for inheriting the 50% of ownership of deceased joint-owner {Note: 'Deceased' is Wife of Co-owner(Husband)} ?

4. What are the legal compliances to be followed by the Husband or son to successfully inherit the 50% ownership of the deceased co-owner?

Awaiting expert opinions.

Best Regards,
Vishal Saha