Hello,
Since the same has been leased to your brother also, therefore without giving a notice to him registry can not be done in your favor.
If however the same is done, your brother can easily challenge the same and get the right to residence.
You mother can send him a notice for termination of the lease.
If the entire loan is paid by you and NOC is obtained by you then the bank will have no objection.
Contact a local lawyer.
Regards