My 13-Year-Old Dog’s Breath Is Rank – Help!

My 13-year-old poodle, Henry, has some of the worst breath I’ve ever smelled. Like, it could clear a room. I know older dogs can have dental issues, but I’m wondering if there are any home remedies or products that actually work I don’t want to take him to the vet. I’ve tried dental treats, and the drops you put in the water, but they don’t seem to make a huge difference. Any recommendations?