Don’t know what to do

I’m 24 and my son is 3 we live with my mom and her husband until i can afford to live on my own. We been here for 2 years and my moms husband constantly bitches about me or my son everyday. There always has to be something that he bitches about. They have a small dog as well and my son can’t even run around the house without him bitching about that because he’s afraid he’ll “ hurt his dog “ we’re confined to a small bedroom all day because he complains about everything. Everything I stand up for myself or my son he threatens me all the time about to hit me or my son I just don’t know what to say or do in this type of situation. I’m saving to move but don’t know how to drive because he told my mom there’s no point in me learning because I have no insurance, I just feel stuck.