I know, seems like a strange quaestion, but ask anyway. If it
was coming from his stomach (from a bleeding ulcer, for instance), then it
will have looked like coffee grounds. Blood in the stomach coagulates when it mixes with stomach acid.
If, on the other hand, it looked bright red and wet, it would not be coming from his stomach. It could, however, be coming from his esophagus. A severe enough case of GERD (acid reflux) can cause a raw and bleeding esophagus.