Ahhhh, I've been doing a bit of research on El Al's operating procedure and on it's website, I found their Conditions of Carriage. Notice that 9.2.2 (a) states that one of your options is to extend the validity of your ticket. As US law states that price mistake tickets must be treated like any other ticket, then had you paid regular fare, the airline would've most likely agreed to extend your stay. Essentially, the airline is in violation of both their own Conditions of Carriage and US law. Also, they have the Israeli laws listed on their webpage and from my understanding of it (it is translated already into English) they may have even violated Israeli law. All of this because they did not properly offer my parents the compensation they are supposed to by their own admission.:
9.2 Cancellation, rerouting, delays and denied boarding compensation
9.2.1 We will take all necessary measures to avoid delay in carrying you and your Baggage. In the exercise of these measures and in order to prevent a flight cancellation, in unusual circumstances we may arrange for a flight to be operated on our behalf by an alternative carrier and/or aircraft.
9.2.2 Except as otherwise provided by the Warsaw Convention or the Montreal Convention, if we cancel a flight, fail to operate a flight reasonably according to the schedule, fail to stop at your destination or Stopover destination, or cause you to miss a connecting flight with us on which you hold a confirmed reservation we shall, in agreement with the Passenger, either:
(a) carry you at the earliest opportunity on another of our scheduled services on which space is available without additional charge and, where necessary, extend the validity of your Ticket; or
(b) within a reasonable period of time re-route you to the destination shown on your Ticket by our own services or those of another carrier, or by other mutually agreed means and class of transportation without additional charge. If the fare and charges for the revised routing are lower than what you have paid, we shall refund the difference; or
(c) make a refund in accordance with the provisions of Article 10.2.