They know the ins and outs of themselves, but their contemplative nature means they will never stop exploring their inner selves. Alternative Perspective: Everything is about to change; that's a happy thing, and a sad thing. We're crying, siblings are tearing up, and parents are full-out bawling. We have layers.
This has its advantages and drawbacks, obviously, but just keep in mind that they are much more sensitive to your words and actions.
Enjoy this time with family and friends. Another bit of advice would be to put away the technology and spend some time outside. Someone who puts a lot of emphasis on labels, designers, or money is immediately off putting.