Someone who is vegetative 99.9% of the time and alert 0.1% of the time is not PVS.
What is it you are arguing here? What do you mean by PVS?
It seems to me that PVS means a person can't communicate it doesn't say anything about whether or not they are conscious. That is to say that they are able to think to themselves but just can't talk or write or gesture what they are thinking.