I don't feel family love for my brother
Have you told anyone else that you don't feel love for your brother?
No, I keep it to myself.
It's not uncommon for people to not love members of their family, so you shouldn't feel bad about not loving your brother. As long as you don't treat him, or the rest of your family, poorly, then how you feel doesn't hurt anyone.
I'm trying to convince myself that they don't love me because they are too good.
It's okay if you don't feel particularly close to your brother.  However, you shouldn't assume that he has any ill will toward you in return.  As long as you are friendly and civil with your family members, you really don't have anything to worry about.