What is a Pretrial Conference? And who attends? And how can I drop the charges?

A pretrial conference is basically just a court date where the parties (the prosecution, defense, "victim," etc.) can discuss the case and report to the Court what the status is. It sounds to me like you can provide your daughter's boyfriend with a defense. You should contact his attorney right away to let that person know. If you attend the pretrial conference, you should relay this to the prosecutor. You can also hire your own attorney to do all of these things for you. Best of luck.

The conference would involve the judge, the prosecutor and the boyfriend's attorney. You do not have the authority to stop the charges, but you can make your desires known to the prosecutor and to the boyfriend's lawyer. If this is simply a misunderstanding, hopefully that will be the end of it. If you have other questions about this case, I suggest that you contact an attorney in Kentucky to advise you.

A pre trial conference is a hearing involving the attorneys,the judge, the defendant and any complainants the prosecutor chooses to have present.

You cannot "drop the charges". Only the prosecutor can decline to prosecute. You can attend the pre-trial conference and let your views be known to the defense attorney and the prosecutor.