Can you transfer membership and can you delete a members name on the basis of only notarized consen

There is a family of 03 people that is Father and 02 Sons Father as (X), 01 Son as (Y) , 02 Son as (Z) There is a flat which is on the name of father as (X)and 01 son as (Y) that is 50:50 ratio Father passed away 11 years back leaving no nominee so the 50% share of father will go to legal heir and will be divided between (Y) and (Z) So now (Y) becomes a major share holder and (Z) so gets some percent of share because he’s a Heir. After fathers death (Y) threatens And manipulates (Z) and makes him sign a Notary consent letter on a 100rs stamp letter stating (Z) should not claim for any right in the said property and should give (Y) the consent to become the sole owner. Under pressure (Z) signed on the consent letter. It’s been 11 years now and past some months back there was no change in the title of the house, the property was still standing on the name of FATHER (X) and son (Y) Few months back Son (Y) submitted the consent letter af to the society after 11 years. (fyi - conSent letter was made 11 years back) Society has now gone ahead with the consent letter and made SON (Y) the whole sole member and transferred his solo name on share certificate as well. Son (Z) spoke to society and mentioned not to remove his Father (X) name on the basis of consent letter. Society mentioned to (Z) we will be taking your signature for NOC but society didn’t send any NOC and society published in the newspaper under public notice mentioning that “anyone who objects to come ahead giving 10days time duration” And son (Z) was not aware of the public notice published in the newspaper. However Son (Z) made a complaint at ddr office against the society that it is deleting his Father (X) name with the help of consent letter only and this was submitted at DDR office within 17 days since public notice was published and same complaint was emailed to society showing them Son (Z) has filed a complaint against society by unlawfully deleting his Father (X) name. Please let me know if society can remove name from share certificate on basis of a consent letter without an NOC