Glad to hear he's okay!
A uncle to my dad had a vein that bursted open, one of the major ones that goes from heart to head (no idea what you call 'em). He was one of a few lucky ones to survive this though! Afaik he have recovered fully.
This is something that happens rarely they said. You also have a very slim chance of surviving it too.
Ah well, it shakes you up a bit. Life is short so better enjoy it while it's still kickin'!