Crosshair ends up leaving the Empire a few years after what happened between him and his twin. He knows that leaving is dangerous, that he's signed himself on for a death sentence, but overwhelmed with guilt, he can't bring himself to care. He wanders alone for several years, surviving and getting by best he can, trying to do his part to injure the organization he once fought so loyally for. He comes across his brothers once, but by that point his silver dye has started bleeding out, and it was easy enough to hide his face and slip away before they saw him. (Or before his eyes could linger too long on the scars across his twin, or the limp in his step, or how big Omega had gotten since he had last seen her, or how happy they had seemed in that one moment). He temporarily works alongside a group of rebel clones, until he realizes that their Commander left out the important fact of her being Captain Rex's wayward batchmate, and he ducks out, not wanting word to get back to his former swuad thay he's still kicking.
He finds his place amongst a group of rebels, several years later (almost thirteen, by his count (how had he survived that long?)) after their medic had come to assist him after an explosion in the streets, and when he had tried to leave she had slammed him to the dirt and grumbled at him in a motherly manner he had never felt before. They were an odd group; a force sensitive human and her twi'lek cousin, twin Amarans (who apparently used to be triplets), an ex gladiator who towered a good foot over his own height, and their medic, an ex slave married to her rescuer, the ship's main gunner. But despite their odd appearance, they took him in, ignoring any excuses he tried to make about his past and why he was dangerous.
(Three months later they rescued a Jedi and her two young children, and realized they really didn't care).
And if, in a year (having lost their Jedi to save their lives and left with the responsibility of her children and uniting them with her still-living master), he'd find himself face to face with an aged Captain Rex, who would recognize him in a heartbeat, then he would stand tall, their little pilot at his side, and his new family at his back. They were here on a mission, after all- rebels stood together.
And if, that year, his brothers would arrive at base, older, shocked, but still his family, then he would meet them head on, across the landing pad, and invite them home.