The degree to which we consider, "locked in" life worthwhile is 2 fold: The degree to which they were trained through their senses prior to being, "locked in" and the possibility of returning to an experience of the world through their senses.

I'm not sure we would consider an infant born locked in and never likely to recover, "sentient"

This is compounded with LLMs by the fact that, aside from a temperature sensor in a server rack somewhere, it doesn't even have the same "hardware" as an infant to experience the world.