They get the piggyback heal whether you Benefic/II/Aspect yourself, them, or another party member. It's counted as having an unspecified source though, so it won't show up in the chat log and you won't see it if you have pop-up text disabled (like a DoT).
I'm not sure why they programmed it that way instead of making it flying text like a HoT tick, other than it might have implications for enmity generation (that is, the piggyback heal doesn't generate additional enmity).