What if Phil never wanted to be a great trainer, but a great father? That the only thing he ever wanted was a son? Someone he could be there for, teach him everything he knows and help him to be the most beloved boy in the world… This could be the reason, why Phil always tried to catch a nymph. The only kind of woman on his Island. A beatiful creature who could bear his child.
Or maybe he HAD a son who died, because he wanted to be a hero and failed… And when Achilleus died (his best mentee before Hercules came), he lost his last hope in making up his failure in training his son.
Is there any background knowledge about Phil??