We have no way of identifying where the Sun was born, what the surrounding environment was, or where the Sun's siblings are right now. This is easy to see from some bare numbers: the Sun's current orbital period around the Milky Way is some 250 million years, and it's been around for some 4.5 billion years, making for some 20 orbits around the galaxy since its birth. There's a lot of stellar-movement dynamics that can happen over those twenty orbits, and any siblings have long parted ways. Similarly, any stellar remnants that are close to us right now are close because we're passing by, not because we were born in their neighbourhood.
As such, whatever the source of the heavy elements in the solar system, it's several billions of years too late to figure out any individual sources.
That said, it is important to emphasize that there is no such unique source to begin with. As explained in the answer you linked to, there are plenty of such predecessors:
There are grains of material trapped inside meteorites that consist of solids that were already present in the pre-solar material. These are important because these grains were thought to have formed in individual stellar events and their isotopic compositions can be studied. These tell us that the Sun formed from material that has been inside many different stars of different types.
Moreover, if you want to place those predecessors, you are fighting against the internal mixing of the interstellar gas on a galactic scale:
Mixing in the interstellar medium is reasonably effective. The material spewed out from supernovae and stellar winds 5-12 billion years ago has had plenty of time to mix throughout the Galaxy before the Sun's birth. Turbulence and shear instabilities should distribute material on galactic length scales in a billion years or less.
This means that the Sun was not born out of the ashes of its neighbours. Instead, it was born out of the ashes of stars that might have died on the opposite side of the galaxy, several billion years before the Sun's birth, whose ashes then got thoroughly distributed by the mixing of the interstellar medium.