I see a potential problem here, in addition to dee_dub's excellent take as always. You made a very bad deal - you paid well over 50% down and then before you had much of any milestone, you paid another 30% or so, leaving only around 18% left for the builder to have incentive to finish and be paid on the job. That's not good. Now here's another problem. He's spent all the money - all the money you'll be paying here on in will go toward materials and NOT to paying him a dime. Thus, in his mind, working for you means he won't be earning anything going forward. This means you might need to do something soon to ensure he's on the job.
If it were me, I'd send a certified letter stating that he breached the contract but you are giving him a chance to complete the work and minimize damages. I would also add that, by doing so, it is in no way waiving any of my rights. In the event he does not do the work, you will need to hire another contractor since the hurricane season is upcoming and the work MUST get done in a timely fashion. If he doesn't do the work in a professional manner and reimburse you for $X by Y date, then you will need to take further action immediately, including discussion this matter with licensing boards, etc. and suing him for all amounts you will have to pay another contractor. Make sure that he must be on the job immediately and that the work is done to your satisfaction. This could exceed small claims court if you need to hire someone else to finish his lousy work - if he shows up at all.
I think you see where I'm going with this. Without the proper incentive, I'm not sure you'll get satisfaction. I hope this works out for you and settling the matter is usually best (and here he should have no notions of thinking he'll be able to do another paying job and put you on the back burner.)