It sounds like a ruptured cerebral anyrurism. But that would have been evident on autopsy.
Iām so sorry.
My guess would be a cardiac event.
My pups sire just died in his sleep at 6. This is a breed of dog where DCM claims over 50% of all dogs so the breeder has yearly testing done (holter etc). Dog had no issues. Necropsy inconclusive. His sire is alive and well at 11. Breeder has very little history of cardiac issues in her lines. So best guess is a cardiac event but we will never know.
