The better solution may be to ask the landlord about ending the lease without penalty, as long as you can help market and find a prospect to rent the unit. You wouldn’t need to spend too much money. Just throw on a nice listing on craigslist and see the prospects start coming in. I would think that as long as you could find another qualified tenant for him that he would be willing to work with your situation.

I was going to mention that even though verbal agreement mean nothing, legally, you could still hold it over your landlords head. Politely remind him about the verbal agreement and ask him to answer what did you mean when you told me that you were wiling to flexible with the lease terms?
You will get a lot further by getting him to tell you vs you trying to tell or remind him.