You know, this is such a generic way of healing her.
In the LN she awoke because her Longinus, Nereid, finally awoke. The fact that she was dormant for 100years and awoke her Nereid Longinus (one which revolves around dragons) at the same time the 2 Heavenly Dragons are rampaging in the real world? That's no coincidence.
You could have at least had him try to wake up her Longinus by flaring his dragon aura on her or something.
DestonDark