In my line of work there ae 3 sides to every story. Yours , his and the absolute fact. Bottomline is you were at the stick when it went in. Crappy situation and my gut feeling is you were hosed and the suit is funding his next big project. Bottomline is dont take control of another persons aircraft unless you are prepared to pay for damages that occur at your control. Especially a high end jet in the thousands of dollars, just bad judgement. How long did u know this person when this happened?
In any case you can pay this character back one dollar per month to keep him off your back and it will have the positive side effect of aggravating the crap out of him to cash or deposit it. A valuable lesson learned here.