I would still be very suspect of a subtle neck injury. Inflammation in the upper neck can be contributing to his leg weakness and the other symptoms. He may benefit from some daily gentle neck traction therapy and frequent icing. He needs to be very careful with resting and sleeping posture. He likely has an injury similar to whiplash. Treating it as such will be helpful.

You could advocate for him by telling them that University of Buffalo research has found that 85% of concussions have these subtle neck injuries that do not show up on imaging. Ask if they can treat him as if he has suffered a neck injury.

There are two specialty chiropractic protocols that may help. www.NUCCA.org and http://www.atlasorthogonality.com/Pa...e/aboutAO.html

You may have to pay out of pocket to get him examined but it would be worth it. Then, you could try to get him treated by WC. Expect a starting work-up to cost $400 to $600 for X-Rays and such.

My best to you both.