It Starts with Us by Colleen Hoover

A kid who looks just like Atlas, and he’s staring right at me with eyes that
look identical to Atlas’s eyes. Does he have a child I don’t know about?
What is going on?
“She thinks I’m your son,” the kid says. “You’re freaking her out.”
Atlas immediately aims the phone back at his own face. “He’s not my son.
He’s my brother.”
Brother?
Atlas moves the phone so that I’m looking at his brother again. “Say hi to
Lily.”
“No.”
Atlas rolls his eyes and shoots me an apologetic look. “He’s kind of a
jerk.” He says that right in front of his little brother.
“Atlas!” I whisper, shocked at every part of this conversation.
“It’s okay, he knows he’s a jerk.”
I see the kid laugh behind him, so I know he knows Atlas is kidding. But I
am so confused. “I had no idea you had a brother.”
“I didn’t know, either. Found out last night after our date.”
I think back on last night and how it was obvious something was bothering
him about the text he received, but I had no idea it was a family issue. I guess
this explains why his mother was trying to contact him. “Sounds like you
have a lot to work through today.”
“Wait, don’t hang up yet,” he says. He walks out of the kitchen and into
another room for privacy. He closes a door and sits down on his bed.
“Biscuits still have about ten minutes, I can chat.”
“Wow. Pancakes and biscuits. He’s a lucky kid. I had black coffee for
breakfast.”
Atlas smiles, but his smile doesn’t reach his eyes. He seemed like he was
in a good mood in front of his brother, but now that I have him alone, I can
see the stress in the way he’s holding himself. “Where’s Emmy?” he asks.
“My mother has her for a few hours.”
When it registers that we’re both off work and I don’t have Emmy, he
sighs like he’s bummed. “You mean you actually have a free day?”
“It’s okay, we’re taking it slow, remember? Besides, it’s not every day
you find out you have a little brother.”
He dives a hand through his hair and sighs. “He’s the one who has been
vandalizing the restaurants.”
I startle at that comment. I need to hear more of this story.