Not as rare as you think. Although, it was not mentioned if it was hemorrhagic (aneurysm) or ischemic (blood clot), I would guess an aneurysm,
" An estimated 6 million people in the United States have an unruptured brain aneurysm, or 1 in 50 people. The annual rate of rupture is approximately 8 – 10 per 100,000 people or about 30,000 people in the United States suffer a brain aneurysm rupture. … Ruptured brain aneurysms are fatal in about 40% of cases."