i find it very weird why BDA has a problem against a married person being a joint owner
anyway you can buy the plot in your name and have the registration done
thereafter you can sell 50% undivided share in the plot to your brother under a registered a sale deed
this way you and your brother would become co-owners of the property
but if you transfer the plot or a part of it within 3 years of its purchase, then whatever consideration you receive from your brother for sale to him of your 50% share, will be considered as your short term capital gains and you will have to pay tax on it as per the income tax slab you fall into
also you need to check if there is any restriction imposed by BDA against the allottee from selling the plot or a part of it
another way would be by transferring your 50% share to your brother by a registered gift deed [which does not have any consideration and hence there will not be any capital gains]
the brother can later on transfer the money for the 50% share in the plot to you which will be considered as gift in your hands and will not be taxable u/s 56 of the income tax act
however please do re-confirm the above with a competent chartered accountant