It must be a Byway as vehicle must use it to get to the school and nursing home. seems very odd to have these three buildings not serviced by a public road, is it a very rural area. How did the council get planning permission for these buildings, or did it give it to itself.
Are any of the buildings new, could the contractors building traffic have damaged the road, or the greatly increased traffic.
Is your friend employed by the school directly or indirectly, she may be able to claim from them as they should have made provision for safe access.
You could try to get the council to take over the road, the residents may go for that for a plice to get off the maintenance and any legal costs or insurance. The coulcil should be shamed into taking it on as it should have adopted it before one or all of the buildings were constructed.
Good Luck