16 and 25, Is this Legal?

Okay, so my neighbor has a daughter that babysits my kids. The other night I heard her on the phone with one of her friends talking about this guy she has been sleeping with (she thought everyone was asleep). She went on to mention that the guy was 25 and she really loves him but can't tell her parents. So being concerned, I told her father the next day. He went off, of course, but decided to not confront her about it until he knew he could do something about it legally. We've spent a week looking for the legal age of ual consent in KY and have found only that the legal age is 16. The only other info given is that a person aged 13 - 15 can legally have with a person no more than 5 years older, and that a person 16 can not have with a person over 18 ONLY IF THAT PERSON PROVIDES FOSTER CARE TO THEM. It says nothing about just 16 having consentual with persons over 21. Does anybody HONESTLY, WITH PROOF TO BACK UP THEIR ANSWER, know the KY law regarding the legality of ual consent between a 16 year old and a person over 21 who is NOT providing foster care? SERIOUS ANSWERS ONLY PLEASE! This is a father of a 10 year old daughter helping out a good friend. We need you guys' help.