How similar is Silver Sentry to the real Superman?

[neatoman]

So, remember this?

Spoiler:

These are homages to real comic book covers. And while that may just be intended to amusing as easter eggs, how accurate are these to real in-universe events? Like for example, if we assume there really is a "Silver Sentress" and this cover does indicate her story is similar to the actual Supergirl, can we in turn assume Silver Sentry is an alien from a destroyed planet and that he has a cousin who is also a survivor of this world?