Oh, they are going to love it!! DISHWASHERS are wonderful!! I went almost 10 years without one..... Shane would joke and say, "I have one, it's called Shell" little turd!! So, the DAY we closed on this place (almost 3 weeks before we moved in) I went back to our appartment and filled up a tote with DIRTY dishes and drove over to the new place and filled the dishwasher!! LOL Those dishes never went back to the old place! Then the same thing with laundry that weekend.... NO MORE laundromat...well, except the weekend of the 17th when the kitchen will still not be done yet.... the floors in my laundry pantry are getting done too.... so the W/D will be removed and re-installed at the end again.
Anyway.... congrats to your folks and to no more holiday dish pan hands!!