Can't find the problem of passing out

I need help for my husband. I'm coming here to see if someone else has experienced the same. 72 year old, 250 lbs, History: He has had bouts of dizziness and vomiting several times over the last ten years or so. Has been tested from top to bottom (literally). Blood work-great. No abnormal findings anywhere. This last time was worse. He passed out cold, no warning. He was out about 10 minutes. When he was conscious, he was confused, not knowing what happened, his address, his age, kept asking what happened, and he kept throwing up. ER doc
ran CT, EKG, Blood work, Everything and could find no reason. He was confused for over an hour and slowly started coming back to his normal self with no memory of what happened. This was three days ago. The ER doc did not admit him even though he is still throwing up and still is three days later. Cant keep very little down, if anything.