The Lodestar Contest

A young boy, fifteen years of age dares his fourteen-year-old cousin to jump off Craggy Rock, a dangerous place they are all warned about. Rocks lie below in several places; raging waters from a waterfall close by make currents strong enough to suck a person under and drown.
After some persuading, the boy's cousin decides to go for it, but after jumping he disappears:

1. Is he dead?
2. Has he been washed downstream and pulled out by someone?
3. Has he time jumped partway down?
4. Has he disappeared into an alternate reality?