What Causes Excessive Gas And Bloody Stools?

My boyfriend has terrible gas and last week was passing blood in his stool since has stopped passing blood in his stool and always has gas that eventually gets him throwing up . Tonight he was cramping and almost passed out he could not pass the gas felt dizzy got white as a ghost disoriented for a minute. Is this something serious I am worried and he does not want to go to er and is now slepping.