first panel of the comic you can check here:
http://bpavlica.deviantart.com/art/Oenni-comics-490856188

Arvo's father got badly wounded and was about to die

Arvo didn't know how to act and quickly slipped into desperation, sobbing his heart out, as he was a strictly trained fire mage and was therefore creatively limited in the use of magic.
Ölse on the other hand didn't have a proper education and the magic she uses she figured out herself - she is far more unique with her magic, which is why she was able to act quick and burn Oswin's wound to stop the bleeding.