How many days is the trip? Are they staying on site at Disney? If it remains as popular as it is right now best bet is to be staying on property for at least 3-4 days and try to get a fastpass for the last day of the trip at midnight 60 days from arrival day when the fastpass window opens!
We are staying 8 days and at 60 days out at midnight I was able to get a fastpass for our last day. I checked for our second day and there were already none left...by morning when I checked again, there were none left for the last day of our trip either!