Is he working on computers screen for long durations?
If yes, the cause may cervical spondylitis due to postural reasons while working.
The rules are that after every twenty minutes, he should look at a distance of twenty feet for a period of twenty seconds.
Neck exercises like forward and backward bending and side ways should be done regularly.
While waking up he should sit for a minute or two before standing up.
Next Steps
He should consult a general physician first for evaluation