I Feel for Steven at the loss of his mother.
He's been there since they were so very small and in Steven's world, his mother was loving and kind. She was what he wanted. They stayed in touch and she provided him her old flat in London (though most likely Marc bought the flat and Steven filled in the info of how he got it as being from his mother). The post cards, the phone calls. He loved his mother and in his world, he had no one else.
He was always reaching out for companionship and no one saw him. His coworkers don't care about him enough to get his name right. His only real outlet is a street performer who can't talk to him and his phone calls to his mother. He never has anything back. No one sees him or hears him.
Even as he finds out that Marc's mom is cruel and caused so much harm and trauma, he still thinks of it as "Marc's Mom" because he still has his memories of his own mother, even if they aren't real. He can't believe that the woman he knows could do this to Marc.
But when he finds out she's dead, this is the real crushing blow for Steven. He is alone and always has been alone. He has lost someone that he never had. Talking into an empty receiver with no one on the other end his whole life.
And as he watches Marc fall apart in the street, struggling with the duality of losing someone that should have been a protective figure in his life but that was everything but…
This is where Steven at last clicks with Marc. They have both been alone screaming into the void never knowing that the other was just on the other side screaming back.
Oh, Steven adored his mother. Was willing to wait for her through all her traveling, called her every single day just to tell her the most mundane details of his life even though she never answered, never called back. Looked fondly at every postcard and every gift she left him. I mean, god, even in that moment with Harrow, when he was threatening to call her, essentially promising to shatter the illusion of her that, at that point, was already crumbling into pieces. He still wanted to defend her, even if she was an idea, even though she was just a myth to him anymore.
That understanding broke him, not just because he had to admit that she had died, not just to Harrow but even more so to himself. But that he also couldn't separate this idea he had of her with what she truly was anymore, and what she'd done to him and Marc. And to be forced to come to terms with that harsh reality in moments.. because if he doesn't, he loses Marc, loses Layla, loses the world. Steven had to lose everything Marc has spent his entire life losing, but in mere seconds, and he manages to carry it while still supporting Marc as they learn to shoulder those burdens together.
That's what a hero does.
I'll be the first one to go on about everything Marc did to keep Steven safe and loved, and the tragedy of everything Marc suffered. But to watch Steven's entire world fall apart and he still somehow manages to come out of it with all his love, his generosity, his heart.. it's a wonderful thing.