how do i make my service dog not behave like moms dog

Hello, im getting a service dog soon, well a puppy to train as service dog. But i live with my mom who has this HORRIBLE behaved dog,like constant barking even in the night, chasing and biting the cats, biting me til bleeding and more. If my dog starts to do this he will be rejected from the service dog training. How do i make sure my dog wont start doing these weird things? The barking gives me panic attacks because its extremely loud (you hear it on the othwr side of the street when the dog is in our house) and the biting me and my cats really scares me. I barely sit downstairs because of that dog so me and my own dog will mainly sit in my upstairs part when the other dog is downstairs (its not home from 9 to 5 because of my moms work and because i refuse to dogsit that dog). How do i make sure my dog won't start barking too because it constantly hears the other dog barking? Do i keep them apart so my dog doesnt start biting me and the cats too? My dog is gonna be a labrador so not a very difficult breed, my moms is this weird looking Hungarian dog with dredlocks, and yes it bites hard. Hard enough to have almost killed my Norwegian forest cat (now i try to keep them apart as much as i can, which works except when my mom js lets them be, because she doesnf accept my boundaries around the dog for me and my cats). The dog also bit me hard enough for me to bleed, this happens around once a week. The dog is already 8 years old so no puppynor teenage behaviour