This is pretty much entirely based in headcanon.
He has never seen his mother's face.
Sometimes she wore her dress low, so that her breasts were exposed. Sometimes she wore no dress at all. But always there was the shawl, a square of linen folded in half diagonally twice over and tied around the lower half of her face, covering everything under her eyes. Usually there was a second shawl concealing her hair, leaving only an inch of white visible at the center of her back. He clung (and clings) to this detail. Seeing it let him know he belonged to her. She was the only person in the village who could have produced him and his sisters, with their pale blond hair.
Sometimes newcomers would stagger in from the desert, or else were dumped there by the pharaoh's guard, and often they were mutilated: a nose, ear, or lip cut off to mark them for their crimes, a tongue cut out for speaking blasphemy against the pharaoh, an eye gouged out for spying. Many of them took to covering their faces.
He would examine the crests and dips in the cloth over her face, to map its shape, and determine what might be missing. He hadn't examined closely enough.
His mother was very subtle. She spoke little, and wore no jewelry, and her tread was so light she scarcely left a footprint. She could lie in wait so still and quiet that you could fail to notice her even if she was right in front of you. Her victims never saw her coming.
She taught him to take what he could, when he could. She taught him to pry the rings off a dead man's fingers. While his sisters, too young for thievery just yet, were learning to spin and weave, he was practicing sleight of hand and misdirection. The other village children could never get anything past him.
Once, he had to create a diversion for her. He was nervous, filled with a dreadful certainty that he would give her away, and he had to think on his feet, but the prize had been well worth it. They got new sandals, and their bellies were full for a month.
She taught him to catch the glint of hidden gold, and to blend in with shadows, and with crowds.
He is sick of blending in.
She taught him nothing of violence, or cruelty. That he learned from the pharaoh's men, when they reduced his home to ash and its people to gold.
The faces of his sisters meld together in his memory—were they twins?
He has never seen his mother's face, and he never will. This injustice cannot go unpunished.
If it seems a little disjointed, it's totally because it's a stream-of-consciousness thing, and not because I suck at segues.