My father has been a chain smoker for 15 years but has quit smoking last year with occasional smoking in a week or so. He has always had problems of tonsils from childhood and sore throat even during summers. Nowadays he has been having sore throat very frequently and also a change in voice and unable to speak clearly sometimes but this goes away on its own and again returns . Gurgling with Betadiene helps him. What can be possibly wrong with him? Please help me, I am very afraid.