Healing a vampire at 0 hp

[mehs]

So a vampire has been reduced to 0 hp and has made his way back to a coffin. The text says that he is helpless for an hour, then regains 1 hp, then stops being helpless and his fast healing activates.

Could an attendant heal the vampire with an inflict light wounds or harm spell to speed it up?


Edit: please give both RAW and RAI interpretations please

[Malimar]

By RAW, it appears that the vampire is helpless for an hour (during which his fast healing does not function) regardless of any healing he may recieve.

Not sure what the RAI is, but I would say the helplessness and fast healing not working ought to be a function of being at 0hp (in which case any amount of healing makes him unhelpless and restarts his fast healing), not a function of having been reduced to 0 and sent back to coffin (in which case the above RAW interpretation would be true).