My mTBI was 3.5 years ago and I had that terrible nausea about 2 months later and suffered. I resisted myself taking Zofran and then gave up and took it. It does work very good. I have to change my diet to control it. Mostly I eat fresh fruits, veggies, Yoghurt etc., I avoid meat as much as I can. Because of my nausea feeling now I can't even take any Vitamin pills besides the sublingual ones.

I have both dizziness and nausea which can get pretty ugly at times. I didn't know what nausea means before my mTBI. Also I tried many meds like Elavil, Cymbalta, Notriptyline, Neurontin etc., which sure messed up my stomach. Now I take only minimum dosage of Xanax which also helps my nausea besides my dizziness. Now I take Zofran only occasionally when stomach throws me in a loop.

I lost about 20lbs after my mTBI and now I gained back. I do understand what your son going through. Hope he gets some relief soon and since he is young he has a better chance of full recovery.