What is the cause of too much coffee?

I don't think coffee can hurt you or him. Too much of it can give you a headache and tired and possibly some nausea. Is he drinking it every day? Has he had any health issues? I don't think he will have any problems, but he will need to drink it everday since he is already doing it. If he tries to avoid adiction then he will be in great pain. Like I said, it probably won't hurt him.

Many healthy people are drinking this much coffee and it is not effected their health in the least. I think poorly filtered coffee can be a concern for one's liver, over a long time.
Today many such questions have resulted in studies that show coffee drinkers are actually healthier than those who do not. Recently, research has showed that coffee drinkers were less likely to get prostrate and colon cancer. A thirteen year Japanese study revealed that coffee reduced by half, the risk of cancer of the mouth, pharynx, and esophagus. A twenty-four year study showed that women who drank coffee were 19% less likely to have a stroke compared to those who drank less than a cup a month. Coffee is now being recommended for those who may be likely to get dementia, as it helps to stimulate the brain.
So when you raise your cup of Java, remember that you are drinking to your health. Cheers!

Two or three cups of coffee a day would be alright, but too much coffee would be bad for health as caffeine constricts blood vessels.