I'm sorry he's been back to the hospital!
My son did six weeks of EN (he was just a few weeks shy of 17 when he started) through NG tube. He ingested 3000 cals per night (he had his formula only overnight). He would insert the tube before bed and remove it in the morning. Once he learned how to do it (it only took a few days to feel comfortable doing it), it literally takes seconds to insert.
To help during the day, my son was allowed clear fluids - pop (no coke/pepsi/etc., just ginger ale, 7-Up, etc.), popsicles (no chocolate), freezies, jello, gatorade, clear candies (like Lifesavers, no caramel/chocolate candies), apple juice (no fibre) and broth.
The broth was especially helpful as he would have a bowl at meal times - not quite a 'meal' but the flavour was more 'food-like'.
We weren't given any maximum amounts of these liquids although we were told to be conscious of the amount of sugar (ie jello, popsicles, etc.). To add some variety, I would heat different flavours of broth with different spices/herbs - beef, chicken, vegetable broth with basil, rosemary, oregano, etc. (just be sure to strain out the spices).
I arranged with the school to keep a supply of freezies in the staff freezer and would send the broth to school in a thermos so he could 'eat' with his friends.
Please be careful with the crackers - one of the purposes/benefits of exclusive EN is complete bowel rest. I'm not sure if crackers would defeat some of this purpose and it would be a shame for your son to make such a big sacrifice only to have the benefit diminished because of a few crackers.
Our nutritionist did warn my son that weeks 3 and 4 were tough to get through but that it would get a bit easier after that... my son did find this to be true. Distraction was also really important, especially in the evenings!
During the 6 weeks of exclusive EN, my son gained 10 pounds but, after the six weeks, he continued with the EN at 1/2 dose, 5 nights per week with a regular diet and then gained almost another 20 lbs over the next six weeks!
EN helped him quite a bit... it took him into clinical remission right away and kept him there for almost two years. He only now (last week) added remicade as his new adult GI felt that, although he was pretty much symptom free, there was continued inflammation that EN hadn't been completely able to eliminate.
If your son is able to stick it out, it will, hopefully, bring him the same benefits! :ghug: