WMG / Pete's Dragon

Elliot is actually Pete's deceased dad come back as his guardian angel.
  • Then the "other kid" could be another child of his. Or he realized now that Pete has a new family, he won't need him anymore and goes off to help other kids. It makes their good-bye that much more heartbreaking.

The next sequel (should it ever comes) will take place in the Present Day with another kid he's helping.
  • More or less; no sequel planned, but a reboot that may be a sequel at the same time, see next entry.

The 2016 "remake" is in fact a sequel
It is just a coincidence that Elliott gets to help another kid named Pete.

Pete is a Targaryen.