Chron's disease

Dear Agnes,
I have a friend who has Chron's disease. He is now 33 years old and has been ill since about 16. He had one operation when the inflammed part of the small intestine was taken out so he's intestines are shorter. He is very slim and has no energy, suffering from diarrhea and several health problems. I recommended boodtype diet for him and we are considering to go on a juice fast. I'd like to know your opinion, what you suggest, what we can do or what formulas do you suggest, anything! I would be very-very happy if he healed and put on some weight. Also, if anybody has similar experience or something to share I'd love to hear any advices!
Thank you very much,
Skylah Tweet