Is he taking NSaids for pain or arthritis? (non-steriodal ainti-inflamitory meds) I was hospitalized this fall with blood loss and nearly had a transfusion; my count only got down to 9. The dr's should have asked this question but on the chance they haven't, you should mention it. There was never a specific bleed sight found; it just happens fast and fierce.
This must be very frightening for you and your hubby; my thoughts are with you.