Omg, it's hard to believe that this could happen. In Ukraine (East Europe) after the 2014 Crimea annexation and after the beginning of the war in the Donbas Region, the currency has fallen about twice. It's hard for me to imagine that the currency can fall so much as in this case described. I think that such situations can be avoided.
For example, I found on the internet an agency - https://yorkmoneyman.com/ and should be a lot of these agencies in different states. I think that prior to taking a mortgage loan it will be a good idea to consult a specialist in this sphere. By the way, cryptocurrency one day may also fall, lol.