Actually i was thinking about all the age regression doujins out there, if the women absorbs the man's life force and turns him into shota, doesn't that technically mean he's gaining life instead?
Think of it as entering the "Fountain of Youth". She can Reduce his age then feed him food until he grows up again only to absorb it when he's an adult. Kinda like a Mock immortality.
Logically speaking, The human Victim should be Old & Withered after the Draining Possess.