It appears that your is suffering from alcohol induced
liver disease, as is evident from rectal bleed and multi-organ failure. His coughing can also be related to liver disease which can cause accumulation of fluid in the lungs and abdomen. Reflux oesophagitis, common in alcoholics, is another cause of coughing. In addition, alcoholics are often more vulnerable to respiratory infections, which cause coughing. These are some of the possible causes of cough in your brother's case. Please consult a doctor so that appropriate treatment can be instituted after a proper diagnosis is made.
Best wishes.