Batter doesn't reach first

[john5396]

This happend to a friend last week NFHS varsity.

Pitcher for the visiting team is at bat. he receives ball 4. The team sends out their coutesy runner while the batter runner is on his way up the baseline. The BR stops 6 feet short of the base and turns and heads for the dugout.

What rule covers this case? 8-4-2-p covers a runner abandoning the base after touching first.