Blood vomiting. No alcohol no smoke.

Sir last friday night my dad(53) suddenly vomit blood 2 times back to back, after reaching hospital he fainted a little, he cant stand a bit but can hear our words and give a reply, and his body become very cold latter emergency doctors give him salain (NaCl liquid) after 2 salain his body came normal temperature. In morning we give him a bottle(350 ml) blood and got discharged. Total 5 bottle salain he took, and I expect he vomit 1Lt blood and blood was not fresh, its like brown/blackish red in color and jelly not like fully liquid. We make a Endoscopy and the report war clear, the doctor(gastroenterologist) said no ulcer was found, so he told to make a chest x ray, he told x ray image was clear but in report ,there was a term like "Prominent bronchovascular markings are seen in left lower zone" and rest reports are clear, so the doctor told me to make a check up from a chest specialist,now in our area not such doctor is available. Sir please help us the reason. No Alcohol No Smoke.