If there is one thing Alex can count on, it is this.
He is not alone.
One time, he threw a jinx at a boy who had said some things about Ellie that even adults would be horrified at. Alex was sentenced to detention, but not without some choice words about Ellie and her kindnesses and the world and its cruelties. The professors did not bat an eye; they merely sighed and told Alex to behave while the jinxed boy was fretted over and sent to the infirmary. There was injustice here, but he could not speak of it outright or else he'd become a whiner. So he kept his mouth shut and shouldered through detention with the stubborn will of an eleven-year-old boy who cared fiercely for his friends. Soon after, Adrian snuck in and slipped a Chocolate Frog into Alex's robes. ("Ellie said thanks, and that your jinx got that kid good," Adrian whispered to Alex, beaming with pride, before he snuck back out again.)
He is not alone. No one is ever alone.
Even among the Slytherins, the purebloods, his "kind", Alex does not fit in. They call him blood traitor and circle around him in halls like he's some disease. But he is not a disease, and he is not a cure. He is a boy who is different than a Slytherin pureblood because he would never want someone else to feel like they're worthless for being something they can't help, like he did. He is a boy who does not want his father's legacy on his shoulders—he wants his own legacy, and he is branded a traitor for that.
But this is also a time when blood purism is frowned upon, taught against, attacked because it is the same thing that Voldemort used as a weapon of mass destruction. And no one wants to go through that again, so the Slytherins who still hold onto tradition quietly give Alex a wide berth. There are not as many of them as there would've been decades ago. There are Muggleborn Slytherins and halfblood Slytherins who roll their eyes at little spitfire Alex, ruffle his hair, and tell him to "go on, scamp, don't cause more trouble than you already have."
(Sometimes a particularly strange Slytherin by the name of Ellie would accompany him to Potions. They would be friends for all seven years (remaining six for Ellie) and keep in close contact for a lifetime afterwards.)
(Or a particular Muggleborn Gryffindor by the name Adrian would see a bit of his little brother, whining about unfairness and magic back home, in Alex and take the boy under his wing with grand gestures and a warm, boisterous voice (but this would be a couple years later). They too would be steadfast friends for a lifetime.)
He is not alone. No matter the choices he makes and which path he takes, he is not alone.
He has a screaming row with his parents. They have intercepted a letter from Aiden and are outraged at the fact that their son is associating with those of filthy blood.
"I did not raise you to become this, this," (this is the first time Alex witnesses his father stutter) "disgrace!"
"Stop dallying around with those mannerless mudbloods." His mother nearly howls. "You are a Zabini, a pureblood. I will not have a blood traitor in my house!"
There are a million rebuttals on Alex's tongue, all emotional and hurt and sharp, but he keeps his mouth clamped shut. He will not give them an opening. He will not break under their words, not this time. Blood may be thicker than water, but sometimes it isn't enough to be family. Sometimes family is not blood. Sometimes you choose your own family.
So with his exacting mother's anguished, furious screams in his ear and disgusted, disappointed glares from his vain father, Alexander Zabini takes his already packed suitcase and walks out of the house where he played with the Bulstrodes and the Mulcibers as a child. He packs up his life, leaves a part of himself there, and never looks back.
He only cries a little because he is a boy who misses his parents, no matter how selfish or cruel they were, because they still sung him to sleep with old lullabies and held his hands and laughed with him. He will keep those memories, but he will not regret walking away from that house. He will not let others guilt trip him for leaving his grief-stricken parents or cluck their tongues at him in pity, because he never did it for guilt or pity. He did it to walk away from his selfish, cruel parents who still hurt him despite their acts of love. Don't you get it? This has never been about tradition or propriety—this is about making choices and being yourself. This is about agency. This is about the people he chooses to surround himself with. This is about making your own family, whether out of your own blood or out of rubble and scars.
There are about seven billion people on this planet, one of which is you. You are not alone. Loneliness exists, but you are not alone. No matter what choices you make, surround yourself with people whose hearts are bigger than yours, who have scars they are willing to share and some they aren't, who are more than aware of life pumping through their veins and their hearts. Meet people who do good for the sake of it, wherever you go. Meet people who care.
Alex shows up at Ellie's doorstep that summer, sniffling from his trip and gripping a large suitcase close to his chest. Ellie's mother quickly ushers him in, sits him down at a small dining table, and pours him a warm mug of Earl Grey tea.
"Do you want some milk and sugar with that?"
Alex considers it.
"Some milk, please."
He watches the milk swirl and bloom in his tea, and it reminds him of the underwater flowers dancing between dappling rays of sunlight outside the Slytherin Common Room's cold windows. Alex takes a scratched teaspoon, twirls the milk into nothingness, and swallows a big gulp.
The warmth travels down his throat and settles in his stomach like it belongs there.
Ellie is already there sitting beside him, while her mother sits on Alex's other side, and both mother and daughter wait patiently as Alex sips at his mug of tea. But there's an urge, an itch to talk as the women stare at him. So he puts his half-empty mug down and struggles to find words.
"I… I…"
They are quiet. They are waiting. He tries to gulp in air like he's struggling to breathe but there's nothing constricting his chest except some burden he still hasn't let go of.
"I… ran away."
"Do you want to go back?" Ellie prods.
Alex thinks.
"They don't want me to come back."
"Do you?" Ellie presses.
There is no hesitation.
"No."
His chest doesn't feel as constricted anymore. His shoulders slump, relieved.
"No, I don't." Alex says with finality, and returns to sipping his tea.
"Well you are more than welcome to stay here, darling." Ellie's mother says, with a comforting pat on his shoulder. Then she suddenly leaps to her feet, like she's forgotten something. "Blimey, I didn't even think about how hungry you must be! Let me fix up something for you darling, hold on."
Her mother stumbles about in the kitchen, fretting over how many days the boy must've traveled when actually he took the Knight Bus here. He still grins at the thought all the same. (Now Alex knows where Ellie gets her kindnesses from.)
He glances at Ellie and murmurs, "Thank you."
She rolls her eyes at him and smiles. "What am I, if not your friend?"
He is not alone.
Alexander Zabini is named godfather of Vi's and Adrian's son, Eden Ahmed-Lee. He is struck with childlike awe as he holds this bundle of squirming life, tiny fingers reaching and curling around his pinky. He sits and stares at this small brown child he gets to watch growing up with all the love and joy in the world. Adrian and Ellie tease Alex a little about how he's de-aged into a little kid, and, to be honest, he feels like a five-year-old kid all over again, staring at this small bundle he gets to call his godchild.
He looks up, his vision a little hazy with tears, and says, "I promise to make sure this kid never feels like he's alone."
But no one is ever alone.