On this one you do need legal advice. As it does not say what Country.  You may be under ussery laws. Or you may need give up your first born son or 12 year old daughter. 

Bankruptcy! Declare full bankruptcy and use the lawsuit to help you in the bankruptcy he says you owe $65,000. Go to bankruptcy Court with that and tell them there's no way I can pay such a bill. Get out from under predatory loans. Start over

It depends what country you are in. Normally that is illegal and is called usury. 

Do not sign agreements. 

You should probably have an attorney review whatever you signed.

If HALF of what you claim is true, INSIST he sue you. In fact, have the attorney you consult issue a letter DEMANDING his next contact be formal service of the lawsuit.

I am willing to bet that he will drop off the face of the earth.

Which Country are you in? He won't  be taking you to Court in the UK as he sounds like a loan shark., 

you hire an attorney

Why keep signing things? Ususury laws prevent them from charging ridiculous interest.

It depends on the contract you signed.

You use “us” and “we”. If there are others that know this they can back you up. Did you keep your original agreement that he signed?

And you say you signed the agreements? Your question should be “how do I prevent this from happening again?” There are usury laws that limit excessive lending rates, but not sure how or if they would apply. You might want to become a conservative like me. Instead of getting what I want right now, I saved up to buy it. I earned interest on the money as I saved it. And when I bought what I wanted, I started saving for what I want next. If you think about it, I only had to wait to buy my first car. After that, I already had the money saved. And if a disaster happens, I can borrow from my savings.