I don't know that I've ever seen a video that really reaches-out to teens. The "families with small children" version obviously centers on the characters and kiddie rides, while the "adult" version has a lot of info on Pleasure Island, romantic dinners, spa treatments, etc. I believe that when you order the planning video from disneyworld.com, they ask which version you want. If you've got time before your trip, order the adult version and have it shipped directly to the friend's home. That might spark some interest.
It may be asking a bit too much to expect a teen to get too excited about Disney. Many people who have never been there probably can't get past the idea of seeing a 6' Mickey or Pooh around every turn.
On our last trip, my 20-something cousin joined us for six days at WDW. He didn't really show much interest in the planning process, although I could tell that he was excited to just be going on a vaction. By the end of the first day, I knew that he was having a really good time. I wasn't expecting any teary eyes while walking down Main Street, but it was a great trip all the same.