You’re asking two separate questions. The first is a semantic problem. Rephrasing, you are saying:
“Commonly, people hold that when one is dead one sees nothing. But saying that one ‘sees nothing’ implies that one is actively seeing after death, but that there is nothing to sense. The common meaning, however, is that we ‘do not see;’ that, in fact, sense perception and all other thoughts cease after death. So, more properly, one ought to say that we ‘do not see.’”
I don’t find this first analysis to be problematic. You’re identifying a common perception and identifying the language used to describe it as incorrect.
But then you continue by asking if, perhaps, the first formulation is actually correct, and that some form of thought exists after other activity in the body ceases. So, let us examine the possibilities.
The first possibility is that thinking and the physical brain are inextricably linked. If this be true, then our ability to think is a function of the amount of functioning brain matter we have. We do know that after death, brain activity ceases, and so thought must cease as well. Anecdotally, we know that after brain damage a person’s behavior and thought patterns may change drastically. This kind of evidence points away from a non-physical brain. If the brain were some sort of interface between mind and body, then such disorders would largely manifest themselves physically. That is, one would have trouble moving, or putting one’s thoughts into action, but thoughts themselves would be unaffected.
The other possibility is that there is some sort of mind or soul separate from the physical body, and either this soul was designed or it was accidentally emergent. If the soul were designed, it would need a purpose. Why else would it have been designed? Certainly an omnipotent God could create a thinking being without need for a soul. We can comfortably assume, then, that God would not allow a non-physical soul to be somehow attached to a physical body that was in the process of decay. The soul would need a raison d’etre beyond life itself (since we’ve already established that it isn’t necessary for life), and would therefore need to engage in its purposeful activity after death. This is inconsistent with your fear.
If the soul is accidental, we’d have to first ask ourselves how this could be possible. We would need to show, for example, how evolution could have stumbled onto a non-physical mind to begin with, and how this would’ve been superior to, easier than, or more likely to occur than a physical mind. It is even less likely that evolution would select a non-physical mind that would continue to exist beyond physical life; after all, such a feature would not make allow the species to survive any better in the physical world. But even if we grant this, and we grant that the soul is non-ambulatory, and that the soul requires sensory organs to sense, then, again, your fears should be assuaged. For the surviving psyche would only be able to ponder itself, and its location or proximity to the decaying body would not be a meaningful concept.