I have autism and my mum doesn’t care

I am a 15 year old male teenager and I have autism. I live with an alcoholic mother and my 17 year old brother. I constantly lose my temper because they talk to me normally and not as if I have autism. I just had an argument with them. Our internet speeds have been slowing recently and I have been using an Ethernet cable with my PlayStation to try and get it to run faster. My brother doesn’t let me in his room, if I go in there he tells my mum and she tells me off. Even if he isn’t in and I need something from in there I’m not allowed in until he gets home and either gives me permission or goes in himself. Another thing you need to know about him is that he will never back down from an argument, no matter how wrong he is. 

Since the internet started running slow and I’ve been using Ethernet I had been asking him if he’s been lagging, he always says “yeah it’s ok”. 

I was at school and he was at home, he went into my room with no permission, I would of had to waited for him to come home if it was the other way round, I complained to my mum and she didn’t care. That was yesterday. 

Today the internet is running very slowly and I ask to have it back. He says no. I say can I have it because I need it to connect and you can connect without if. He says no. My mum is here and she just says “he’s using and it’s in his PlayStation so you can’t take it.” I said “he’s not using it he’s in here lying on the floor.” They said he is updating and downloading. I WAS UPDATING AND DOWNLOADING WHEN HE CAME INTO MY ROOM AND TOOK IT!! BUT NOOOOO ITS PERFECTLY FINE FOR HIM TO BRAKE HIS OWN RULES. He says “Why do you need it today it was fine yesterday.” He has said previously that the weather and precipitation can effect the internet speeds. I said “because It is colder today then yesterday.” He says “how do you know it is?” I said “because I was skiing yesterday in the sun with a clear sky.” (dry slope). He says “How do you know today is colder when you haven’t been outside?” I say “the sky is cloudy today reducing the amount of sunlight on the earths surface, therefore making it less warm. Yesterday there were no clouds letting the sun reach the earths surface and warm it. And actually I just went and took the bins out.” He says that’s not difinitive evidence. I tell him to go outside and check for himself, he says no. I’m getting very annoyed right now because he is being annoying on purpose and my mum isn’t trying to help me when he is clearly trying to provoke me. I ask if I can at least reset the internet to try and get it to run faster. He says no. I ask why. He says no. I get pissed, go into the kitchen, get scissors and I try to cut the cable. My mum and my brother are laughing at me. My mum steps in and tells me to stop, she says I’m being ridiculous and that my brother has done nothing wrong. I’m stood there, with autism, shaking with anger. And she tells me off, she doesn’t care. She treats me like I’m normal. I’m not saying I should receive special treatment, I just want people to think about my autism when the speak to me. My brother is SELF-DIAGNOSED with autism and my mum always protects him and says “it’s not his fault, he is autistic.” I can not remember a single fucking time when she has protected me like that. And never once has she taken my side with an argument against my brother.

What do I do?? I’m am losing my mind.