Why do the things little kids say not matter?

I have a little brother that is 9 years old, and he is always calling me fat, gay, retarded, and how much he hates me, even though I'm none of those. He also tries to make mean "jokes" on me, but he is really bad at it. He is also always trying to wrestle with me, and when I decide I will, I always make him hurt himself (which I find hilarious because his scream sounds like a little girl) but he always wants to do it again the next day, and saying these mean things are getting a little annoying, so I get my dad to take him away, because I don't feel like dealing with him. I stop talking to him for awhile, and tries to be all friendly but I still try to ignore him. He always thinks I'm not ignoring him anymore if I'm laughing or having fun (mostly with my older brother, who I never have a problem) just like last night, him, me and my older brother were playing an old Namco game called Rolling Thunder, and we saw 3 cougers jump into lava, and we laughed alot, and when I laugh, he thinks I'm being his friend. Just earlier before everyone woke up, I was awake looking at my messages on my phone, because KJB (542542) keeps texting me this annoying dieters message, and my little brother was STALKING ME in my BED and thought I was on a diet, and trying to loose weight, but I'm perfect weight for my age. Also, how do I stop KJB from texting me certain messages I don't want, and if everything my little brother says and does is normal for his age(9), or am I just pathetic and can't take these little things? He also has had TWO phones already. His first one was bad, and he accidentally decided to skateboard with it in his pocket, and broke it. He has his second phone now, but is asking my dad for a iPhone 4. W-T-F?? Doesn't my dad know that he broke his first phone, and can't be trusted with a really expensive phone? I only had one phone (I'm upgrading to a cool phone this July :D) and I have a iPod Touch 4g. Thanks for reading all of this :)