My Dear Fazal Mistry,
I assume you are one of the Landlord of a building , in which x tenements, residential rooms or shops are being rented out by your grand father I beleive the building is locate in commercial area of metro xcity, say Mumbai.
I understand the building must be 50 years old, or more
If these are true facts, the building must be in dilapidated condition and the municipality is entitled to demolish the same for safety purpose.
All of you are bound to maintain it, or the tenants can claim in court of law to do the needful.
Let the tenants demand re-development., and the court order accordingly, whereby, you can compro- settle with a builder, who is ready to redevelop it with his fund.
The builder will do the necessary, and pay your part of money, and deal I his own way to the left out minority owners of the building.
I suggest this way, as you are interested in selling off, and collect your part.
In case it don't work out, we will discuss other alternatives.