To avoid any unnecessary legal hassle , note down the following.
As per law seller is bound to disclose to the buyer any material defects in the property or in seller's title thereto of which the seller is and the buyer is not, aware and which the buyer could not with ordinary care discover.
Any omission to make such disclosure is fraudulent and if buyer wish can take criminal action against the seller.
So you mention it in deed that buyer is fully aware of the present physical condition of the building being around 50 years old.
Otherwise, a wicked person if wish may drag you into legal trouble by that fact that building is not in proper condition or it has been damaged significantly during the transaction period itself .
As to bank loan, it is better to ask bank not here. A lawyer is not supposed to answer such question. It is not within his professional jurisdiction.
You can ask what Mr. X can legally do?
But please do not ask what Mr. X will do?
Hope you understand it.