my son is 9 and was dx at age 7.
Those are actually two very good options.
AS far as NG tube your child may be able to drink the formula orally without a tube.
My son did no food for 9 weeks - 7 cans/shakes of peptamen jr a day.
not the most pleasant tasting thing but worth a try.
some kids can drink it JMROGERS child drinks his orally.
others need a tube.
some use the tube only at night then pull it during the day.
Imuran has scary side effects but so does tylenol - docs just don't remind you of those sideffects
Imuran just means lots of blood draws so the docs monitor everything really closely so they can catch anything if it comes up.
DS was on 6-mp (similar to Imuran for about 8 months).
The meds were not strong enough for him and it caused his AST/ALT numbers to increase so the gi added a few other meds.
PErsonally we chose the EEN route first sincec it has not bad side effects with the 6-mp.
later we needed pred but at least we knew we had tried formula.
my son still drinks some formula to make sure he grows like a normal child since that is a big issue for ibd kids.
It is tough but getting your child back smiling and growing makes the scary meds - alot less scary.
hugs