Is it unusual to survive multiple strokes?

Depends on degree: Stroke is the 4th cause of death in the us. Mini strokes can shorten life expectancy and the effect is more significant in patients older than 65 yo and patients with history of heart disease and previous stroke.

No: Survival from a stroke depends on the type of stroke and the size/severity of the stroke. The more strokes a person has the more brain that is lost so the chances of survival decrease with each event.

Actually common: With our current stroke treatment medications and rehab steps, we not only can prevent many strokes, but also can restore patients to improved functioning. A number of patients experience several very small "lacunar" lesions which cause impairment but not death.