Negative Promethethus Test and Crohns Disease

Hello,
My 17 year old son had not been feeling well for two years - general fatigue, constipation followed by bouts of diarrhea, some bone pain (probably from low vitamin D level of 13) and weight loss (5'10 - 150 to 125). After much bloodwork which did not show crohns or celiac, he was told to just stop drinking apple juice and he probably had IBS. Still, he did not feel better and a dietician refused to treat him without a biopsy. He had a colonoscopy and an endoscopy last month which showe chronic active ileitis and hyperplastic lymphoid follicles in the ileum, chronic active inflammation in the rectum and focal active chronic inflammation in the small bowel, no evidence of villous blunting, biopsy for the distal esophagus in which a special stain for intestinal metaplasia was focally positive and there was no evidence of dysplasia. Overall it said the inflammation that is present in the esophagus, rectum and small bowel was non specific and associated with many different types of etiologies. The gastro said this was an atypical presentation of crohns and crohns was hard to diagnose, but it was probably crohns. He put him on entocort and pentasa and omeprazol(sp?) for inflammation in esophagus. Then, he said to have Promethesus test to make a definitive diagnosis. The Promethusus test came back "negative for IBD." My son started the meds, doesn't really see a change yet, but it has only been 5 days. I don't want him on meds if he does not have to be. I work for a prominent doctor who has a strict autoimmunce diet which my son will probably NOT be able to abide by, he is a teen and cant bring blended green salads to lunch or juice three pounds of veggies in the morning. With this information, do you think it is likely he does not have Crohns? I am hoping he does not. We are scheduled to meet with his gastro in a 10 days, the earliest he can get in. He diagnosed him and then didn't even say he wanted to see him again! I will be looking for a second opinion. I lost my husband to cancer and I do not plan on having my son's health jeopardized. Thank you for your help.