Landlord (homeowner) trying to back out of a singed lease!

[Jarvis Smith]

This topic is for a friend of mine.

They signed a lease for a property and expected to move in, in 8 days. Now homeowner is saying property is in uninhabitable. Saying roof needs replaced and septic/plumbing lines are bad and are trying to back out of lease. Homeowner is saying that they can’t afford the repairs. Again lease has already been signed and deposit has been given.
Friend or person leasing wants to move in regardless of repairs and is willing to negotiate lease terms just to move in, since they planned their whole lives around this move. What can a renter do to protect themselves? I was under the impression that a landlord has to provide a habitable home before signing the lease, and if not they must fix the problems and homeowner is saying they weren’t aware of the repairs until a few days ago. Isn't this something they should figure out before offering the property to lease?

I recommended my friend to get an inspection to really know whats going on and to possibly file a lawsuit for the total lease amount. I just want to know what the plans of action they should take.
Thanks!