I’m calling that Rumpel used the true love potion to have the power to do anything: including bringing people back to life. It is his “contingency plan” just in case his son died.
Ooo! That’s an interesting theory! A lot of people keep pointing out that Baelfire may already be dead, and there’s no way that possibility escaped Rumpel’s thought process. So, the true love potion may be able to bring people back to life. It’s already proven itself to be an effective antidote against curses that imitate death (sleeping curse). So, anything’s possibile.