rape and child abandonment
I have a backstory-esque plot for how Amphon ends up alone at his age. He is a child of rape. I'm undecided on the motives, but his father took his mother one night, when she was left defenseless.Tools needed for abortion are hard to come by, and people that know how to use them even harder, so this wasn't a viable option. Birth control is a little easier, but the mother never thought it would happen to her, so never took any. So she carries Amphon to term.
Still, a child wasn't part of her plan so to speak. She takes care of her baby only as long as she needs to, and leaves him behind as soon as it's "appropriate" or "feasible" (around age 5). They don't meet again after this, and wouldn't recognize each other in a crowd. Amphon doesn't know the circumstances of his birth either, and that really isn't what concerns him. While he is able to fend for himself via his own enginuity, he is lonely, and tired in a way.