Normally Vegeta can be a light sleeper. It's mostly from needing to wake up at a moments notice in battle, however even he will give into exhaustion when pushed to a breaking point and sleep through stuff that would normally wake him up.

It's how a certain weight had gone ignored during his sleep, becoming aware to it as he blinked awake and needing a moment to register that something was there with him. Something that most certainly not his wife, or any one or thing else he recognizes. Well, he knew it was a cat, but not one he recognized at all. Certainly not one he's expecting to be resting on his chest.

Or bapping him on the nose. Vegeta pauses, before grumbling out, "Who the fuck are you?" He's not really expecting an answer. It's a cat after all.