Perhaps she should have read it first. Now, she's going to cast a provisional ballot, which is almost certainly NOT going to be counted. These mandated changes certainly suck but they were not unclear. People need to stop letting emotion overtake reality.
You'd be better off taking her to her county board of elections, requesting a duplicate ballot from the clerk, and voting there and handing it right back to the clerk.
I have a feeling that a lot of little old ladies in these senior communities did the exact same thing. They threw it out because they want to vote in person like they have done in decades past. Murphy was probably counting on this.