I mean yeah you're right it would be hard to predict exactly what he would do. But I just meant realistically/practically speaking if he wanted to continue his current life as is. I don't know too much about law and stuff so just wondering if there were any loopholes, strategies, etc.. he could practically do to win the case or not pay the money. I'm thinking his primary argument will just be that he never explicitly agreed to all the terms/conditions (only implicitly through payment of rent and notice of 30 days).

After some research, I found this:

"An enforceable bilateral agreement requires an offer, an acceptance, consideration and a meeting of the minds upon all the essential terms of the agreement."

I'm pretty sure he will use the argument that there was no clear acceptance or meeting of the minds upon all the essential terms of the agreement, which resulted in a very non-solidified agreement, and that it was my own fault for not taking the due diligence to follow a more formal approach. Or something of that sort..

Either that argument or that he did notify me and put in effort to find another roommate replacement but was extremely difficult due to the COVID crisis b/c the apt was very close to NYC (aka blame it on corona). Not sure how valid of an argument either of those are and I may be overthinking this..But like I said I'm just trying to hope for the best and prepare for the worst..

I know he works for a rather well known tech company in IT and that his job is important to him. So I know that he will definitely try to defend him self from getting a wage garnishment so his company doesn't find out.