This is an unfortunate circumstance that happens all to frequently lately. The simple answer is that your lease governs your ability to get out of the contract. You still could be in breach. If I were you, I would try and talk with him and request he let you out. If that is not an option, I would call his bank. This information is public record in Florida, as his mortgage was filed. They should be able to explain your rights to you a little better.
I would go back and look at your lease agreement. My position here is that the Landlord may be in default for failure to perform his duties to you by not being current on his mortgage payments. In that situation, if the default would apply, you might be able to provide written notice in accordance with the lease notice period that you are terminating your lease. If you are able to do that, it is important that the written notice state that you are terminating based on the Landlord's failure to pay his mortgage payments.
However, even if the bank is going to possibly foreclose, it will be several months before this can happen once the foreclosure actually begins in the court system. The mere threat of a possible foreclosure does not mean you will be needing to find another place to live in a few weeks. These proceedures take a little time. Plus, if the bank takes over, you may be answering to the bank as your new landlord.