The Statute of Limitations in Maryland is 3 years. That means that the Landlord would have to file suit within three years of when his cause of action arose. If the Landlord filed in 7/10, it appears to be too late. However, the Statute of Limitations is an affirmative defense that must be properly pled and presented to the court. Your son can't sit back and say, "its been too long." He has to convince the court that the Landlord's suit violates the Statute fo Limitations. There are several factual issues that must be reviewed to make sure that the Statute was not tolled etc. Please consult an attorney. Good luck.
The Statute of Limitations in Maryland for a breach of contract is generally three years. Depending on exactly when the eviction was done and when the tenants no longer had use of the property, the landlord may have waited too long to file suit.