If he wants the building to demo and redevelop, then he can choose to let his units stay vacant (or put some tenants in - this scenario works either way) and then let the building deteriorate until the other units are undesirable for rentals and devalued for purchases.  

In my opinion much more restrictive flood zone code devalues these properties as it will seriously preclude investors from continuing to improve properties and make additions such as garage apartments due to additional cost in building and lot prep. 

And it did devalue the remaining lot you have.

From my comfy armchair, I can see how today’s situation in Kiev - far enough removed from the war areas, and being the economic and cultural center - could be attractive to those who know their way around the local bureaucracy to not have to pay an “overhead” under the table at every turn.I can see how the deeply devalued Ukrainian currency can make the purchase potentially even more attractive.

Like I said, those in the know can predict these events, go to cash right before it happens and buy up the devalued assets right after the crash.

Most have no skills and the resulting work will devalue your property resulting in additional cost for th einvestor to undo their work.

They say it'll be a hassle and devalue their homes.

All they are really doing is saving the prevailing mortgage interest rate (at best) at the cost of devaluing the income on the property.

Your purchase  costs would be gone , sales costs gone  and even possibly the home Devalued .Most of the time landlords wont allow subleases and will likely not allow Airbnb .

This will likely lead to you being blocked by the Co-op board from purchasing any additional units due to the fact that turning the Co-op into a rental building will devalue everyone else’s units.