After Cassandra found the truth of what had happened and saved the Divine with Galyian's help, Avexis was only a child about 8 or 9 years old at the time.
She grew older and had found love with another elven mage named Nathaniel and they had a child together. A girl they named Jericho. After the dalish Inquisitor Luna Lavallan appeared out of the Breach, the fighting between mages and templers were growing fierce.
Since she has the ability to control wild beasts, she was often sought by blood mages until she knew that the only person besides Cassandara was Galyian and she asked him only one question,"Will you watch over my daughter old friend? She needs someone to raise her and keep her safe while this war rages on."
He agreed and took the sleeping child into his arms and knew that she was a mage like her parents. So, since he knew that Cassandra was the book to remake the Inquisition, Galyian knew that they needed to be with them because of his healing magic and he joined as a healer.
Of course the Seeker was surprised to see him after several years and asked after Avexis when he nodded to the little one in his arms and said,"She was trying to keep her daughter safe and no she isn't mine by blood Cassandra. Her father was a fellow elven mage named Nathaniel. I knew that he was poisoned with deadly nightshade and as for Avexis. I think she died protecting herself from rogue tepmlars."