Legal Question in Business Law in Massachusetts

Much more information is required to make a reasonable judgment on the question.

However, I would refer him to the story of Facebook and Zukerman's former partners and clients who sued him and collected.

Not to make light of your situation, but if you have watched "The Social Network" then you know quite a bit about information partnerships. The details are extremely important here, and if there is something of value I strongly recommend you reach out to an attorney. Best of luck!