Helmet comes off during a tackle, due to prior foul?

[jTheUmp]

A fellow official sent me this this morning:
High School Football Player Gets Helmet Twisted Backwards, Leveled

For those who can't view the video:

Christian Young of Viewmont High School had his facemask yanked so hard by a defender on a play that his helmet was backwards, essentially blinding him. The referee threw an obvious flag, but the play wasn't dead since Young still hadn't been tackled. He stumbled blindly while fruitlessly trying to fix his helmet when—oh, now the play's over.

When the second defender hit the runner, the runner's helmet came off.

Do you make the runner go out for a play or not?

I say no, because, IMHO, the foul by the first defender was the main cause of the helmet coming off, albeit after several seconds had elapsed.

What say you?