p.s. - as a commish, you now have an opportunity to give some MEAT to your rules and to show your league you can drop a HAMMER.
I'd go public with what happened, explain to the league you can't rectify the situation by being nice, so the fallback posiiton is the rules - give him his points from his week 3 lineup, replace C-Pepp with Plummer on his roster, give him no QB for the week (in direct contravention to what I wrote above, I know), and treat it as a lineup short a QB.
In the future, if someone complains about a lineup subvmission, you say: "Remember when so and so couldn't get a lineup in b/c of a CAR ACCIDENT? Well, [insert owner's excuse here] doesn't cut it either. Sorry, but we wrote the rules for just these types of situations. Next time, remember to submit a lineuyp early in the week and you won't have these problems."