What does a big sister need to say/do when her little brother says you don't even like me/ you love your friends more than me?

He probably feels left out. You're his big sister, you're everything to him. Let him in. Tell him about your day and ask him about his. Hang out with him and defend him to your parents. If he's young, take him somewhere he likes, spend the day with him, buy him ice cream or something every so often. He'll love it.

just be nice to hinn and prove to hinn that you like hinn after all

just give him a hug and tell him that you will always be his big sister and will be there for him if he ever needs you

Give him a hug, say, "You mean the world to me, buddy".

Could be a phase, or it may be that he feels his friends are the only ones that are there for him. That he cant talk about his problems because no one will care or he will be made fun of. It could be because he feels you has been lied to his entire life and is starting to see through them. Thanks to my narrsicistic mother, I resent my sister and my father and I abhore my mother.

What you need to say depends on why your brother is getting such thoughts, something ought to have happened. How old is he decides if its natural or if he is not emotionally strong enough as kids always look up to there elder sibling and sought to there attention.