Empty threats
Here, we have a classic roof-caving-in problem that the landlord never bothered to look into. Not only that, but the heaters the tenants had running on full-blast all night did nothing to raise the temperature by a single degree. There must’ve been extremely cold winters in that hellhole, especially with the gaping hole in their roof.
When the tenant tried to leave before the lease was up, the landlord actually threatened him. He wanted the tenant to fork over more money for no reason. He was banking on the tenant being young and stupid to cave to the unreasonable demands. It didn’t work.