Hi sir... Bad smell is due to so many cause **soft and hard deposits(Plaque and calculus) **Multiple decayed tooth **Diabetes mellitus **Gastric disturbance(Gastric ulcer,GERD) If the bad smell is due to deposit, you need to undergo scaling and polishing if it is due to multiple arious tooth, you need to undergo simple filling or Root canal treatment depending on the depth of caries.... If your father has Diabetes mellitus, Gastric disturbance kindly consult with general physician

Hi firstly u need to check if he has any decay or any swelling in nearby gums and check if his tongue is not coated. If so then u need to see a dentist immediately....if only once the causes are removed then u can go for mouthwashes like any chlorhexidine combination.

Do warm saline rinses 3 to 4 times daily

First check with ur dentist for cleaning and polishing. Bad smell could be because of various other factors like gastritis, less water intake, ENT problems, sometimes even diabetes. Considering his age check up with a physician too.

Hello sir, first need to do a clinical examination followed by scaling, if any decay compulsory fillings must be done, if any decay is deep then Root canal can be done to save your teeth, followed by oral hygiene maintainence by brushing twice daily and using chlorhexidine mouthwash twice daily diluting in water....

No any home remedies are cure. You should consult to dentist near by your area. Your father need of scaling and polishing.

Firstly get his regular scaling and polishing done from a dentist. Then Home maintainence by twice a day brushing and flossing. Use a mouthwash like clohex or Colgate plax