I'll preface my comments with the fact that I do not live in your state, but there are some real estate and legal concepts that are somewhat universal. An contract or services agreement was entered into by two willing parties, each with certain respective duties and obligations. Most management contracts are going to have a similar set of standard terms: identify the parties, the term, fees, duties, arbitration/mediation, termination, etc. I recommend a detailed review of your agreement, with your real estate counsel if that's available to you. Those terms are going to dictate the circumstances under which you can terminate that agreement. Although it explicitly states:
"It shall be effective on April, 2013 and shall be for an initial term of 1 year. This agreement shall automatically renew for successive terms of 1 year each unless either party gives the other party written notice of its desire to terminate this agreement at least 60 days prior to the conclusion of any such renewal term, in which case this agreement shall terminate at the conclusion of such term"
this does not account for any other breach of the agreement which could serve as grounds for terminating the agreement (i.e. performance, good faith, etc.).
That being said, sometimes tenants just move out regardless of the diligent efforts of the managing agent. As long as they acted reasonably to avoid the premature move out and they effectively communicated that to the owner within a reasonable amount of time, and then subsequently took reasonable steps to mitigate the loss and days of vacancy...that may just be a part of being a property owner. Of course we don't have all the facts of your specific situation but I hope that at least provided some perspective. Best of luck to you and your uncle.