Fragile / Deteriorating Neighbor Property

I am prospectively renovating a Brooklyn row house and adding an addition to the rear of the property. The neighboring property is in very poor condition, specifically with regard to an extension off the back. Large sections of brick are missing, and supporting elements appear to be rotting and unstable. While there are numerous DOB violations on the neighboring house, but none of them appear to reference this extension. Architects and engineers will obviously be conducting all of the appropriate review and oversight, and we would take the utmost care and respect with any renovation, but this extension appears ready to fall at the slightest movement. Does anybody have experience in a similar situation? In a worst case scenario, who’s fault is it if this structure fails? I would reach out to the neighbor to discuss this directly, but it is an apartment building and appears to have been sold to an entity that I haven’t been able to track down.