Question on share certificate of cooperative housing society

Hello Exerts, I have a question regarding share certificate of co-operative housing society. here is a quick background.. My mother got the ownership of a flat /apartment(through succession) in one of the Housing societies in Thane Maharashtra. This flat was owned by my late father. We have got necessary court order to this effect. However, I was given to understand that the share certificates should be collected by members in person. Unfortunately, due to my mothers age she is not able to travel to collect the certificate in person. So I was planning to take a letter of authorization to collect the share certificate. I also have registered GPA on my name from her to deal /take care of her apartment. So with this background... Is it mandatory that my mother should collect the share certificate in person? or can I collect it in her behalf since she is not able to travel? Thanks a lot in advance for clarifying my query. Best regards Vijay