I'm not a lawyer, so this isn't legal advice. For that you need a lawyer. However . . .
It's likely the landlord is in breach of the lease. Your lease probably says something about the landlord maintaining a safe and habitable property. From your description, yours isn't. So--with a lawyer's guidance--you should be able to break your lease and get out of there.
As for the property damage the mold and moisture has caused, I'm not sure if renter's insurance would have covered it. (Side note: In any case, though, you should always have renter's insurance. In future properties, make sure you do.) However, I'd take the landlord to small claims court for the damages you've incurred.
I don't know the property but, from your description, it sounds as if the maintenance man probably is correct.
Good moving getting a building inspector out there. If the property is condemned, for instance, the landlord may discover that--as expensive as it may be--it's cheaper to fix the problem than lose the property.
As for suing the landlord for fraud: Check with a lawyer, but probably that isn't your best course of action. Anybody can sue anyone for anything, but the real question is whether you can win. And if so, is there anything to collect?
One of my favorite sayings is "Follow the money." In this case, follow the money. The money's coming in to the landlord from tenants such as yourself. Cut off the money--not just in your case by legally terminating the lease but in taking action (such as through the building inspector) to cut off any prospect for the landlord to generate income.