First of all i do require proper history since how long has he been having an addiction of Tobacco and how much Packets of tobacco he has consumed since last many years?
Need to examine your oral cavity area thoroughly to look for fibrosis or any area of ulceration.
How many fingers is he able to open up his mouth. ?
Next Steps
Need to diagnose properly for further management.
if at all this is a case of Submucosal fibrosis then treatment will depend on grading whether to give steroidal injection Or require other modality of treatment.
Health Tips
stop consuming tobacco as early as possible.