What are the law related to land lease and license and the possibilities available for him as well as his clients?

E is the personal agent of N, who owns two apartments. E is out of town for a business meeting. It was winter and snowing. A young couple who had been employed by a local school approached N and wished to take one of N’s apartments on lease. N’s lawyer was more than happy to escort them to the apartment where they signed on a license agreement for 5 years starting from 5th July 1998. After the couple paid the advance payment of $300 the keys to the apartment were handed over. After a week, the couple approached N with one of their close friend who wanted to rent a single room. The same lawyer was engaged to fulfill formalities of the rent agreement with the new tenant. However the new tenant was given one of the two keys to the room as there was a bad pipe that needed to be visited by the plumber every now and then. The plumber comes to the room and checks the pipes at the washroom whenever he can. E arrived home a month later and announced an increment in the rent fee which neither the couple nor their friend agreed to. The couple’s argument is that they have a lease agreement while this statement was objected by E. On the other hand the friend did not wish to pay the rent as per the agreement but asserted that he will only explain the reason at the court. E is in need of competent lawyer who can help him in this complicated situation.