Step dad / animal neglect?

My step dad has a 14 year old dog and she's blind, she can't stand or move, she has diabetes, and she CONSTANTLY is sitting in her own urine and feces while whining and barking. There is a room (disgustingly enough it's RIGHT next to the kitchen) and it's full of matted in feces and pee so he had to move her to another room which is right by the entrance doors to get in the house. he used to have a carpet cleaner but it broke and he never fixed it so now all the feces and urine is just there.. I'm 16 I have a 15 year old sister and a 5 year old sister. My mom and my step dads family has tried so hard to get him to put her down but he refuses.. This place is a dump. My mom and 5 year old sister live across the street with my little sisters grandma now. So me and my 15 year old sister are stuck upstairs so we don't need to be around the filth. I'm scared my step dad will kick us out if we call animal control and he finds out it was me.. What can I do? He's hardly even home so she's always barking and whining because she can't move and stuff. Thanks for the help