I don't think you're correct. She was able to swallow her own saliva. My understanding is that the alleged husband would not allow her the therapy she needed to regain her ability to eat and drink on her own.
Read the guardian-ad-litem's report. She had three swallowing tests and failed them all. Some people in PVS can tolerate small amounts of saliva, but they can't take water or other liquids. Also, IIRC, the autopsy report confirmed that she would not have been able to swallow.