I expect they will be very tired when they return. Are they downsizing?
Downsizing? I'm not sure.
When they bought this house, they very much up-sized. And all four sons were out of college and out of the house by then, so...
However, I do suspect they are looking for something a little smaller, and a bit more manageable. Right now, there are three vacant bedrooms, and three(!) full baths that are not in active use. And I believe my Mom has started thinking "smaller" too in regards to her need for furniture and other home decor. Oh, and I believe my father is actually seriously thinking of retiring. Finally. I'm not sure if my Mom is considering giving up her job just yet.
But the big factor are the property taxes. They got hit big this year. Their house was valued at just over $500,000 last year. This year, the tally came to $784,000! They were happy with the increased assessment, but the accompanying property tax increase was not welcome. Most of the property assessments in Fairfax County experienced the same seemingly exponential increase.
They're actually looking at some places in suburban Maryland - a good 45 minutes out from DC proper - which seems a bit too far out to me (in many ways). I think they're going to end up staying in Virginia if they can find an agreeable area. I heard Manassas mentioned. And with the grandchildren nearby... We'll see.
I actually suggested they look down in Richmond, since the property values down there are quite the bargain compared to Northern Virginia. They could actually buy a nice place in The Fan,
and a nice-sized house on the northside or southside of town for what they'll most likely get for this house.

But I also think a two bedroom townhouse would suit their needs just fine right now. Guess we'll find out soon enough.