Brisa -
She hates being alone, but she pushes through it, forcing herself into her room whenever she's sick. She doesn't let anyone in her room until she's over the sickness, and comes out in a slight depression.
Virgil -
He doesn't speak at all, and he doesn't tell anyone he's sick. He doesn't want to be around anyone, and if anyone so much as glances at him he's got an attitude.
Unless it's you, then he just avoids your gaze.
Tom -
He acts the same, simply letting out coughs and sneezes occasionally. He also doesn't want to be around people as much. He's over it quite quick, however, as he has a fairly strong immune system.
Talyn -
They're literally the most quiet person on Earth. They don't want to speak, sneeze, cough, laugh, or even breath too loudly.
Grayson -
He spends all his time around Ethan.
Why?
Whenever one twin is sick, the other twin is sick.
Ashton -
He doesn't go outside, let alone out of his room. If he's on tour, he doesn't dare leave his bed. His label gets angry about it, but honestly, he just doesn't care.
Noah -
He's whiny. That's all. He doesn't do anything except whine.
Deja -
She resorts to annoying people. Just everyone, ever.
Harper -
She's oddly quiet, and if she speaks, her voice comes out so quiet and she hates it with a burning passion. Her immune system is weaker than most people's, so she can't really do much. She's sick quite frequently and it takes away her toughness.
Asha -
She hates being sick. Being the baby of her family, she's constantly being pestered about taking care of herself.
Leon -
His voice is quite literally the only thing that changes, it's gravely and rough instead of his usual chilled and laid back.
Rowan -
All she wants is cuddles, she doesn't want you to get sick, but all she wants is cuddles.