Answer: The answer is in the explanation
Explanation: Ok my first internet resource would be to go on and watch Dr. Eric Berg videos and figure why he has this eating disorder. Then I'D ask him, I will ask him if we could start a Ketogenic and Intermittent fasting diet together to get rid of those symptoms. And what he might be experiencing is probably cancer because losing so much weight has to be a sign of cancer.
I hope this works ^^ reply in comments if you need anything else!