Do you have a juicer? If you don't I think you should get one. You need to get any meat and prossesed food out of his diet and juice fresh fruit and carrots to clean him inside.
Don't let him drink anything but real juice and water. No soda.
It may help you to read what this DR. has to say. http://www.drday.com/
James 2:15 If a brother or sister be naked, and destitute of daily food, 16 And one of you say unto them, Depart in peace, be ye warmed and filled; notwithstanding ye give them not those things which are needful to the body; what doth it profit?