My brother is a veterinarian and he called it a stroke, maybe he said that so I could understand bleeding in the brain. We had just lost our mother from a stroke.
Most “strokes” in dogs are not truly strokes.
Actual real strokes in dogs are very, very rare.
Maybe he used it as a catch-all term for these, which are fixable if the vet knows what they’re looking at.
http://www.petmd.com/blogs/thedailyvet/jlee/2011/may/do_dogs_get_strokes-11223