Your only 10 years old, and Elijah is too much overprotective of you, still you have a illness and which makes Elijah overprotective of them, so he signed up for a experiment on himself so they could heal you

Doctor: "I suggest your brother will be the perfect trai-"

Elijah slams his hand on the table

DONT YOU DARE lay a finger on my brother either which kid you choose it IS NOT MY BROTHER!