I have a 10 yr old dog, he has suffered from stinky breath before so had his teeth done at the vet and all has been fine. Now my question is what would cause really bad breath... it is so bad that when I'm turned away from him cooking tea at the stove the other evening I could smell his breath from behind me! before he had to yawn right next to me for to say eek. He has seriously bad dry eye which I am trying to cope with but has steadily gotten worse these last 2 months would it be connected me assuming eyes ears throats are all connected?

Really it could be anything

If it's that bad then maybe he needs to see a vet? 

I had a similar problem with my old bitch (now 11 years old, but 10 at the time of problem starting) The vet gave me some malaseb (I think that's what it was called) to clean her jowels, not the mouth. The problem was a bacterial infection where the canine teeth were rubbing the skin. It flares up from time to time. I would speak to the vet to find out where the actual smell is coming from.