Background - before brain tumor

Jason was born on June 12, 2008.  He was God's gracious gift after we lost our twin babies, Hailey and Kailey.
He was a perfectly healthy and cute baby!
He was growing well without any problems until he was about 5 months old when he slowly started to refuse his formula and it was always very challenging for us to feed him.  He used to take more than 30 oz of his formula a day without any problems but it became really hard to feed him even 20 oz a day.  With his feeding refusal continuing, he basically stopped growing.  He was born at > 95 percentile for weight but by the 6 months of age, he had fallen far off the chart, less than 3 percentile for weight.
He was diagnosed with FTT (failure to thrive) at 7 month and his pediatrician admitted him to a local hospital to find out why he was refusing feeding and stopped growing.  They ran all kinds of tests; tested his heart, lungs, GI tract and brain for any abnormalities but found nothing wrong.  During this hospital stay, he was started on NG tube feeding to help him gain weight.  NG tube is a tiny tube that is inserted through his nose to his stomach to help him get needed nutrition.
After starting NG tube feeding, Jason's dreadful vomiting saga has started...also NG tube made Jason even more orally aversive.  He didn't want to eat & swallow anything while having his NG tube.
We had to take NG tube out because his discomfort was so evident and oral aversion was getting worse.  After a few months of battling to feed him by mouth without any success, we had the G-tube surgery when he was 13 months old.  G-tube is a feeding tube directly inserted to his stomach to feed him.   It was a very hard decision to give him a G-tube but by that time, Jason was so anorexic and cachectic, he was basically all bones and skin.  With G-tube and a new formula (Elecare) he started to gain weight.  However, his vomiting continued even with many medications and slow, continuous feeding.  Something was still not quite right but nobody really knew why he continued to vomit.
With his weight gain, our next goal was to teach him how to eat by mouth again.  With G-tube feeding and specially with the bad-tasting new formula, he stopped eating anything by mouth.  He was 100% G-tube fed. 
Even with "failure to thrive" and G-tube feeding, his physical development was on tract and he was meeting his milestones.  He started walking around 11 months of age and he was very very, I mean, VERY active boy, who was like the "energizer bunny", always on the go, up and moving, climbing on things...but things were starting to change...