Maybe he's a candidate for the less invasive heart valve replacement technique.
That's probably it. Aortic stenosis is the most common valve dysfunction we see with old age, and it can be replaced in a minimally-invasive manner.
They go through your artery and do it all with wires. Super cool stuff, it opens up treatment possibilities for elderly patients that couldn't tolerate an open-heart procedure.
The other thing to consider is that the valve has to be soft and foldable to be transported through your blood vessels so it's not as durable as the mechanical prostheses. Rated for 10-15 years. So they only really do them for patients that aren't expected to outlive the heart valve