Yep, I must agree. At the very most, you would be summoned to provide your testimony as a witness as to what really happened. The judge isn't going to allow for that kind of suit. I'd suggest that your buddy files a claim with his liability insurance carrier, have them pay for a lawyer to defend him and for your time as a witness if you are needed.
I had a case once where we caused about $10K in damage with a cable trencher to some unmarked and unknown lighting feeders at a stadium complex. My insurance company spent more than that in legal fees, etc. and won the case. They then counter-sued the GC on the job and won that case as well. Even I didn't think that they should go to such an extreme, but they said that the only way that they can curb these frivolous suits is to hit them with a heavy 1-2 punch.
