Don't overlook the neck injury. My son was having similar symptoms to yours and one of our first big breakthroughs was getting his neck treated. Some things we did to turn the corner:
Chiropractor - 'Atlas Orthogonal'
Physical Therapy for balance
Eye therapy for sensory issues
MCT oil and butter in coffee

Supplements: fish oil (higer in DHA), MCT Oil, High Absorption Turmeric. All of these help with neuro-inflammation.

The brain is 60% fat. Fat is good fuel for your brain and helps put out the inflammation fire.

Good luck