Hello, my name is***** and I have over 20 years of experience as a veterinarian. I am sorry to hear that your fellow Stedman has a collapsing trachea. It must be a very severe case where he is coughing so much and unable to properly oxygenate his tissues if he has secondary heart enlargement and they are recommending surgery.
There are two primary types.
One is more invasive and involves putting artificial plastic rings on the outside of the trachea to support it. This requires a longer anesthetic and more tissue trauma when the rings are placed, but the effects from this procedure should last the longest.
The other procedure involves placing a stent inside the trachea to keep it open. This is less invasive and creates less tissue trauma, and it is a very quick procedure and thus anesthetic time is less. The downside is if the stent shifts or breaks it is no longer effective and may cause more inflammation. With the newer stents available this seems less of a concern.
Dogs that have a positive outcome from surgery, achieving an airway opening that is almost normal, can have a pretty normal lifespan, as long as the implant stays functional. It's tough to say what his lifespan will be before surgery without knowing how successful surgery is.
But if your fellow is experiencing secondary effects on his heart I think that surgery, particularly one of the newer stents, is well worth trying because medication isn't controlling the progression of his disease, and thus his lifespan will be shorter now if nothimg else is done. I recommend that he see a board certified surgeon to discuss surgery because they can give you the best idea of prognosis given his situation.
Please let me know if you have any further questions.