Real estate attorney from MA I could run a quick question by?

[Michael Zack]

My current tenant is breaking the lease 3 months early. I've agreed to charge him half month's rent to break the lease and I want it paid independently of the security deposit. He's refusing to do so and wants me to use half the security deposit to break the lease (He's bitter that I'm doing a walk-through of the apartment to assess damages after he moves out instead of with him before he vacates the property). 

This is the response I got from him when I told him I'd be sending a payment request through Cozy for half months' rent..."I've already sought out legal advice and they tell me your previous communications are sufficient to break the lease without me needing an official lease break document. Again, you're not getting another dime from me. I expect the refund in 30 days or I'll see you in small claims." Seems like a bluff, but is a text message saying that I'm allowing him to break the lease sufficient, or does an actual legal document need to be signed?