My kiddo also used an NG tube. My daughter tried drinking formula and she did get used to semi-elemental Peptamen Jr. but was never able to drink enough to even maintain her weight, much less gain. So then her GI told she had to try an NG tube. She was VERY resistant (she was 16), but tried it and honestly, though she was uncomfortable the first few nights (she did feeds only at night at first), she was fine after the first few days. In fact, in about a week or so, she could insert her NG tube in less than 10 seconds. She chose to insert hers every night and remove it every morning so no one at school had to know, but if your daughter is home-schooled, then she could keep hers in. In her case, her Crohn's was controlled so she did not do EEN (100% formula) but supplemental EN just to gain weight. Initially we started at 60% formula and 40% food. After getting used to the tube, she declared it was WAY better than drinking formula and she would never go back to that!! She was hospitalized when we first started the NG tube to watch for Refeeding syndrome, but it was for days (like 4, I think), not weeks and she did not develop it.
She later developed Gastroparesis in addition to Crohn's (delayed gastric emptying, in her case unrelated to the Crohn's). She dropped down to 80 lbs at 5'2 and developed an arrhythmia and then actually did develop Refeeding Syndrome (electrolyte abnormalities which can be very serious because the body is so unused to food) when she had a different kind of tube placed (an NJ tube that goes past the stomach into her small bowel since her stomach did not empty and she had started throwing up NG tube feeds). That was very scary and her doctors said that if she did not accept the tube, her organs could get damaged. She didn't want an NJ tube because it has to be placed by interventional radiology and so must stay in all the time. So we watched her weight drop from 96 lbs to 80 and it was so scary. I had no idea how damaging being severely malnourished could be until her doctors told us - it sounds silly but I just didn't know.
Finally hearing her organs could be damaged and a bribe (my husband promised her a kitten
- I recommend smaller bribes like new clothes or something, but she was 18 at the time so we could not force her to accept the tube, so a kitten it was) made her try the tube (and that kitten is now a very happy cat we all adore). For that, she was placed on 20-22 hour feeds and 85% formula and 15% food. It took a while, but she went up to 105 lbs which had been her normal weight. It took a few months to gain all that weight back but she felt SO much better once she was on tube feeds - she had been absolutely exhausted and dragging herself to school (she was a senior in high school).
Many GIs now allow kids some amount of food - usually the ratio is 90% formula and 10% food or 80%/20%. There are studies showing that does work for most kids - not all, but most. That's usually done when the EEN is used as a therapy to induce remission and not just when it's supplemental for weight and growth reasons.
She did later do 100% formula for 16 weeks and honestly, she found that very, very hard. We also did not eat in front of her and in the summer, we grilled outside as much as possible so she didn't have to even smell food. But many kids are able to cope better - in fact, sometimes the younger they are, the easier it is. That was just last year and she was 24. At the children's hospital we went to, which has one of the best ped. IBD programs in the country, they teach kids as young as 6 to insert their own NG tubes.
I know it is really overwhelming, but she can do it! There are lots of videos on youtube of kids inserting their own tubes if she's interested.