Hi, your friend suffers from a Pre-Malignant condition called as Oral Sub-Mucous Fibrosis. The cause for this condition is Chronic eating of Supari with Ghukta/tobacco in heavy quantity. Cure for this condition is there, but first and foremost the Habit of eating Supari in any form must be stopped. As the condition is in late stage medicines won't work. To some extent Injections are to be given an tried for mouth opening if not then Surgical mouth opening is the only option left. Ask your friend to consult a Dental clinic nearby or any Oral Surgeon for better understanding of the disease. Thank you.

This condition of your friends is known as oral sub mucous fibrosis it is in stage 3. first thing to do is ask your friend to quit the habit and den take him to dentist he ll give u daily dosage of tablets and weekly dosage of injections they should make him better if not a minor surgery should b done.stage 3 is and advanced stage of this pre cancerous lesion better consult the dentist as early as possible.