I'd suggest, as we have discussed, concentrate your search on his parents. They have addresses somewhere. His sister may be married with a new name. I'd also concentrate on My Space, or other social network.
Who knows, who might contact you, after you try to contact them.
Since he and his sister went to high school fairly recently, they surely had many friends at the school that might know where they currently live. Tyler would be 20-21 and his older sister may have gone to the same high school. I hope you are able to communicate with one of them in the near future.
Many of the these searches have stop signs. They are best ignored, and go around them.
I hope you get resolution soon.