I would confide in your brother more. I wish I was lucky enough to have a professional in my family. My father used to have a stressful time with work too. He would come home irritable and depressed and would argue with my mother. The pressures of the job are coming home with your dad and your mom is starting to feel anxious too. It sours everything and their snapping at you now. It's not right that they take some of it out on you. Please talk to your brother or another professional. Your brother may not be objective in this case actually. I wish you peace.