Just to add to the EEN chorus... I don't think there's much info I can add, just my son's experiences...
He was diagnosed at an older age than your niece, he was 16 but our hospital was also very pro EEN and that was the preferred treatment option, even over steroids. He did six weeks of exclusive formula (no food except for clear 'liquids' - broth, jello, clear popsicles (no chocolate), etc.). He used an NG tube overnight, as Maya's daugher (so inserted at night, removed in morning and, again like Maya's daughter, he quickly learned to do it and it took seconds). He used an elemental formula - Tolerex.
After the six week exclusive period, he went to a regular diet but continued with the overnight formula at half dose for the next two years.
Only to show the difference in weight that the formula made... prior to being sick, my son was approx. 140-145lbs. After being sick for a few months, he dropped down to approx. 120-125lbs at diagnosis. If my memory is correct, he gained 10 lbs over the exclusive period, and an additional 20 lbs over the next three months (while on the partial EN). Over the next couple of years, he reached 175lbs (it was all 'heathly' weight, ie not the sort of quick weight you can gain with pred). Of course, some of this was expected 'development' and growth but, my point is that the nutrition he received through the formula allowed his body to develop and grow in a healthy way.
He continued with the overnight NG tube feeds until he left for university. By this point, he had started remicade. Upon leaving for university, while not on the tube feeds anymore, he continued (at my insistence, not GI's) with 1-2 Boost shakes each day. He's now finished university but still continues with the shakes most days (it's now become 'habit' for him to grab one for breakfast - better than a fast food breakfast sandwich!
)
While I can't 'prove' it, I've always believed the steady nutrition he received helped his body heal and stay as healthy as possible.
While it may be harder for an 8 year old to understand the necessity, if she can be convinced, it can only help her. And the tube, likely a tougher sell
, can be an even better option in that there is no argument that 'I'm not hungry', 'I don't like it'... it's done overnight, no effort needed, no taste to deal with... but, I can imagine, it would be a tougher sell to an 8 year old. :ghug: