ᐅ Sell the entire property or opt for a partial sale with reinvestment?

There is a large property in the family located in the center of Dresden. It is a residential area—surrounded by 6-story or even taller new apartment buildings. The land is currently occupied by a very old factory building. The owners do not have the funds to demolish this building and replace it with modern new construction. On the other hand, the ongoing costs and rental income are just about breaking even. If income continues to decline, the property could financially ruin the family.

So the question is what should happen with this "factory land." It is quite certain that it could be completely redeveloped since there are multi-family buildings all around. Adjacent to this land is the family’s own business property (including land), which is not intended to be sold as it is their livelihood.

The immediate idea was, of course, to sell the entire factory land. Its value is estimated at around 1-2 million (minus demolition costs), without going into details here. The money could be taken, divided among the family, and essentially spent without long-term benefit.

However, there are also grandchildren who are struggling to establish themselves in Dresden. The family would like to support them over the long term and believes that a rental property would be ideal. Coincidentally, the grandchildren are trained in property management and could help oversee the project.

So the idea came up to sell only part of the land to gain liquidity, demolish the old building, and construct a multi-family house—ideally in collaboration with an investor who would buy and develop the other half. Of course, everything would need to be carefully calculated to see if this is feasible and if the land will generate enough value.

Is something like this possible, or is it just a scam? What would you do?