Old house

We have an old house at Central kolkata , which is a joint property of my father and my uncles.All my uncles and my father are deceased. We have shifted elsewhere due to infrastructure and space problems 19 years back.Children of my uncles reside in that house.We had kept our ground floor room and first floor rooms locked due to our legitimate rights. As a result, the ceiling on the ground floor room has collapsed now .A lot of costs is involved in renovating it. The rooms are going to collapse again since they would remain locked in future. We are not going to stay in that house ever in future and it is not possible to maintain 2 houses by us( including the present house where we are presently residing).My cousins donot want to handover to a promoter nor will we be allowed to give it out on rent . We understand that even if we renovate the rooms now, it would collapse again after a couple of years since they are going to stay locked. My cousins are also not ready to buy our share. Leaving the rooms in this condition may cause accidants. Giving away our portion to our cousins means we would be deprived of our share in case the property is sold out or handed over to a promoter. Considering this, please advise what can we do - can we write to Kolkata Municipal corporation stating that we cannot repair . What is KMC likely to do in this case ? Regards