Family issues

My mum always supports my brother. My brother is 20 years old and doesn't do anything in the house. As first generation kids from immigrant parents, I am responsible for everything. I have to call and book appointments relating to my parents, the house, bills and read letters and transalate. I also have to clean the house and put food on plate for my brothers. On top of that I also work part time and have done well academically, went to a good uni and now got a job that most 21s never get. My brother who is 20 years old doesn't not help at all in relieving that burden. Constantly compares himself to his 18 years old brother and whenever I tell him he is old enough now. He is very lazy doesn't do anything around the house and just places game 247. Doesn't try to get any work experience or anything. Yesterday, I wanted to workout in the living room for 30 mins and he told me I shouldn't and that it won't change anything and that he wants to watch the TV. We had an major argument and I tell my mum. She instantly supports my brother and say I treat both of siblings differently. So I had an argument with her. Today she mocked me and said I can't even cook a proper meal, and how can I argue. I don't know what to do, but am I wrong?