Totally different legally vs illegally. Legally I would think it would almost be a piece of cake for Terri or Kaine, or Desiree. I also wonder about DD with the hair, impersonating Terri.
You walk into a passport office with your own valid passport and apply for your child (who you would need birth certificate for.) I imagine Terri would have liberal access to this, given involvement in school.
They verify you are a parent or guardian, and wham, your kid has a passport.
They might ask him to take off his glasses to take the pic- some do, some don't. Ditto on hats, etc.
Then to actually fly out- a parent or guardian could walk him to the gate and he could either fly attended (I imagine not, considering people would have remembered him by now) or with another adult (much less likely anyone would think of it.)
He'b be in Europe before anyone knew he was missing.