For the amount of money apparently invovled in this situation, you would be probably better off suing this defaulting contractor in your local small claims court without the need for an attorney.
You could send him a written notice as to what your conditions may be for him to finish the job(which should include a date certain). Then, if he fails to comply, file your case with your small claims court.
Since you are already considering speaking to an attorney, you should speak to a Massachusetts attorney about the specifics of your situation. Massachusetts has laws that address home improvement contractor's, so there may be other claims that you have not identified.
Small Claims court is limited to $2,000.00 in Massachusetts, so you would be limited to that amount if you file in Small Claims. If the contractor has breached the contract you may consider sending him notice that you are canceling the contract due to his breach and abandonment of the job and seek another contractor to complete the job. You can sue the contractor for a return of your deposit and you may also seek to have the contractor held liable for any amount over your contract you need to pay to get the same work done.
Many attorneys will provide an initial consultation for no fee, and with no obligation.
DISCLAIMER: This answer is provided for general, informational purposes to the hypothetical questions posted and does not create an attorney/client relationship. It is recommended that you speak to an attorney to discuss your specific legal issues.