Was she able to get a seat reservation in advance, or in online checkin?

It does indeed look like she has been bumped to standby due to overbooking.

There are still options tonight to get to Munich via FRA with LH or UA for example, so in your place, I would call the CS line, explain the issue and ask if there are options for rerouting. Particularly if she is able to arrive at the airport in time to catch the 5:30-6PM departures to Europe, there are load of options.

Alternatively she can arrive to the airport in time for her flight, which will either possibly result in her downgrade (space available) and a 75% refund of the value of the segment, a no-show and return to J, or, a rebooking to one of the now far fewer alternative connecting flights.