5th Foul Question

[rockyroad]

Partner calls 5th foul on home team captain...informs coach and player. Player walks toward bench, but coach says "Go tell them I want them to run 25 on defense while I figure out who to put in!" Player turns to walk back out to teammates and give the message, when partner steps in and tells player to stay right there by bench...coach gets irate - "I've got 30 seconds..." yada yada...was able to defuse situation enough to not have to T coach...in locker room, partner is absolutely adamant that the rules says dq'ed player must stand by the bench until replaced and can't be with teammates on the court...I can not find anything in the book about that...anyone remember reading anything about this before???