Hi there!
Well, without a clinical evaluation it would be difficult to determine the cause of his symptoms or if this is related to the previous injury/ malalignment. Possibilities that may need to be considered include neuro-muscular issues, skeletal abnormalities, growths/ masses etc. It would be best to consult a primary care physician initially and depending on the diagnosis made/ suspected, it can be manage accordingly or specialist care may be sought.
Hope this is helpful.
Take care!