My understanding is that the B main has 2 laps completed and will start as such, and therefore since he did not take the green for the B main, he would not get to run. However, not sure that doesn't mean he can't take a provisional for the A if he is eligible?
I believe he would have qualified for the B, however, since he did not start and the B field was set, I do not believe he can repair the car and join the field.
I could be wrong, but didn't the B push off and start the event?