Don't do anything. Don't act on anything.. Let it go and let it pass...
Doing anything with this young man will hurt your relationship with your daughter. It will be irreparable or at the least take many years to repair and it won't have been worth it.
How awkward would it be to continue with this guy and then have a huge fight happen between the daughter and the boy and then have to have Thanksgiving dinner sitting around with everyone not speaking and looking a the floor in discomfort. The fact that the relationship between your daughter and this boy isn't going anywhere is not a factor here. Don't let that sit in your mind like it validates the possibility of you having a relationship with him