1. You are associate member and your deceased brother is its original member of the CGHS in reference to context.
2. No associate member of a CGHS has any property rights over flat held by the original member to whom he is an associate member.
3. It is the nominee of the First member (deceased brother) who claims right over the shares and the interest in the flat on death of the original member (i.e. the member whose name stands first in the Share Certificate) and on admission of the nominee to membership of the Society.
4. An associate member has no right over the shares and interest in the property of the Society and when the original member dies his associate member automatically ceases to be an associate member.
5. Nominee is merely a trustee. She (your brother's widow) does not get ownership rights in the property till the original member is alive however this is not the case in hand.
6. On the death of the original member (your brother), the nominee has to apply for membership from the death of the original member along with his death certificate.
7. Further in the event of death of the original member nominee/ nominees shall submit the application within 6 months for membership.
8. In a case (which is not clear from your query) if there are more than one nominee on the death of a original member (deceased brother) such nominee shall make joint application to the society and indicate the name of the nominee who should be enrolled as member. The other nominees shall be enrolled as its Associate member unless the nominees indicate otherwise.
9. The nominees shall also file an Indemnity bond in the prescribed form indemnifying the Society against any claims made to the shares and interest of the deceased member in the property of the society by any of them. The Society shall then transfer the shares of the deceased member in the property of the Society to the nominees.
10. There are other procedures when no Nomination is done by original member (deceased brother of yours) in Society flat share transfer which can be discussed separately and meanwhile find out from your widow bhabhi if your brother left behind a nominee for the flat in question or not!
Observation:-
However in above reply what I discussed is about how to get the share transferred of a co-joint flat in a CGHS to you, but from title of your thread post I could not follow what agitation your wife has to all these as here the dealings is going to be purely between your widow bhabhi and you moreover you are meeting the loans and your lifetime your wife has no share / claim in such dealings, or am I missing something here?