Each year, schools or other libraries that have to close for a season can have their pick up locations turned off.  However, this does not affect currently active hold requests that chose that library as a pick up location.

I would suggest a feature either in preferences or in the individual library next to the pick up location switch that would, if enabled, suspend that hold when triggered, flag the hold as needing attention, and notify the patron that the hold has been suspended until they choose a new pick up location.  This could either be invisible to the staff, and the check-in would then go to the next patron in the queue, or it could alert the staff member at check in and give them the option to trigger the next hold or ignore (I think the first option would be less staff intensive).

The patron's hold list could list the item as suspended, and needs attention.  Once they choose a new location, it would unsuspend, and they would not loose their place in the queue.  Or they could choose to ignore, and wait for the location to open, which would reactivate the hold (based on the needing attention flag), or they could choose to cancel the hold.