Suggest Treatment For Low Hemoglobin Levels

Question : my sweetheart started smoking cigarettes and pot from an early age, he says 8. He got married at 20 and became a heavy drinker, the drinking may have started earlier but that's when I met him. He got divorced 7 years ago and did a lot of meth. He got clean 4 years ago and we have been together for two years. He has had problems with frequent diarrhea and a prolapsed rectum with bright red bleeding. He went last year for an upper endoscopy and just had a lower endoscopy because the bleeding persists and he feels dizzy a lot. Sometimes he falls down. Both scopes were negative. Two weeks ago he had pneumonia and he is still coughing so he went back to the clinic two days ago and they drew a lot of blood and indicated on his requisition that they were going to do a drug test. He still occasionally smokes both cigarettes and pot although since the pneumonia not so much. Yesterday he was told his hemoglobin is 4.9. My question is, what else can we do to find the cause of his low hemoglobin? He was taking iron and will start again tomorrow but I am concerned that his liver is no longer able to make enough red blood cells to keep up with his blood loss, and ironically his smoking cessation will lower his RDWs, will that also lower his HGB?

I don't have any of his labs with me but we can go to the hospital tomorrow and get a print out of his most recent labs as well as any drawn in say the last two years to identify any trends