I’ve cared for other people’s pets with congestive heart conditions (and some grandparents of mine, too). Life becomes a bit of a tight-rope walk of balancing fluids, foods and meds just so.
The last dog I took care of with it was a mini-poodle that lived to be 18 or 19yrs old. She was on the typical cocktail of meds. The poor thing did huff and puff which is quite typical with this condition. She was a fiesty little girl, so I knew she wasn’t going anywhere anytime soon (I think I began care when she was about 14yrs old).
If you plan on treating your dog, just know that he’ll require quite a bit more rest on the meds, especially if this is your first time treating his condition.