I believe that you are going to have to do some serious on-the-ground research for this family: wills, estates, deeds, court records etc., probably in both Bracken and Mason County. I did not find any other sources online that I thought might solve the problem. I note that there are a lot of family trees online, but most seem to be copying from each other, and none have info on Luke's parents.
I did locate Luke in Bracken Co in 1850; the name was indexed as Harben. There was a young boy living with them who might be a relative. Also, there was a John "Harben" nearby.
Changing county boundaries and the formation of new counties is something you'll have to keep in mind in early research. Also, Kentucky became a state in 1792, so records prior to that may be in Virginia.
Good luck with this.