Warning: profanities and rude language ahead

My little brother (17) is extremely rude and condescending towards everyone in the house, my mom especially. My mom is lenient, so I feel like it makes him think he can get away with his disrespectful behavior. Whenever she asks him to do anything (he has absolutely zero responsibilities except school) such as dishes or taking out the garbage, he will tell her to shut the fuck up and often times if we are lucky for him to do it- he takes half an hour to two hours to get started and will wonder why my mom will be frustrated. He makes it sound like a burden when we ask him to do ANYTHING but play on his phone or computer. I just came home from college, so I am starting to see this behavior. To make things worse, even if she asks him for simple tasks such as a reminder to “eat your lunch, go to bed, brush your teeth” he will tell us to shut the fuck up on the first time asking. When we try to correct him and tell him why his behavior is extremely disrespectful and rude, therefore unwarranted and why he shouldn’t do it- he will proceed to claim they’re just words, we are bitches, easily offended or “dummy bitches” and it escalates to a whole new argument. Other profanities are used against us. The worst part is it feels like he thinks he is right and is above everyone, as he never submits or apologizes- and will talk down to us claiming we are extremely stupid, or even worse- attempt to put us down by comparing us to people with autism or Down syndrome. He calls my mom a “retard” on a daily basis. This makes me so mad because of how inappropriate and offensive it is, especially to people born with disabilities. Is there any saving this kid?

We have tried correcting him, arguing with him, punishing him (taking away his devices) and so far nothing works. If my mom takes away his phone or gaming system, he will terrorize her by banging items or constantly badgering her for it until we give it up. Even without them, he acts the same way.