Honestly your feelings are valid and your parents should treat you both equally with love and care you don’t deserve to get ignored by your parents especially when you’re sick but let me tell you something your brother has nothing to do with it everytime you get angry at this remember that your brother is innocent it’s your Parents fault and by the way have you ever tried to talk to your parents about this ? Maybe they’re doing this because they’re too busy dealing with ur sick brother? But either way they don’t have the right to ignore you like this I know how it feels because I’m not the favourite child and I got treated so unfairly by my mother too ! And I know that I’m just a stranger but if you needed to vent anytime I’m here ! Hope that they realise that what they’re doing is wrong