His body had turned to ice.
His Pokemon divided and went off on their own to train around Mount Silver.
They never speak their own names or make a single noise, training themselves to be ever-silent as their trainer was and still is.
Sensing your arrival as a trainer climbing up Mount Silver, his Pokemon climb to the top before you and surround their lost trainer and take their positions; most burying themselves deep within the snow as Red's Pikachu waits by it's trainers feet, watching as the challenger approaches.
Espeon uses it's powers to rotate Red to face the challenger.
The fight begins as the Pokemon individually take turns to battle without order, going by instincts and past training alone.
Once you defeat his team of Pokemon, you approach Red, his frozen figure, ever-the-same throughout the past battle - a smile adorned on his face
You reach out curiously to shake his hand, only to watch as his form just blows away, as if it were snow.
Upon awakening, the Pokemon split ways again, believing their trainer had managed to move on to a better place.