It has been a few years since ASA. But... I believe a BR cannot back away from advancing to 1st (can stop but cannot back-up).
Sounds like the runner gave up his opportunity to advance and should have been called out when he first abandoned any effort to advance.
FED rules are different. 8-2-4 "The Batter-Runner shall be called out when: The BR fails to advance to first base and enters the team area after a batted fair ball, a base on balls, or on a hit batter... [therefore not out until the BR enters the dugout area].
Someone will correct my ASA interpretation if wrong.
