Really Need Help

this is going to kinda of be a long post so you can fully understand my situation

I have a bichon frise he is about 8 months now we got the dog when he was around 4 months untrained. Well I am 18 years old male its my mothers dog why she got him i have no idea but anyways. here's a little background my mom works night shifts 9pm - 6 am im never home. My mom sleep during the day til she works in the night so her day is sleep work sleep work so why she got the dog again i do not know. So basically the dog never goes for walks only in the night around 11 pm when i get home so he walks once a day. My mom was trying to train him to use the pee pee pad but he tends to keep using the washroom on our carpet in my room in the living room and we hit him and take him to the pad. He uses it on the pad sometimes and i rub his tummy and everything when he does and tell him good dog but he still uses it on the carpet or floor no matter how many times we hit him and tell him not too. Is there anything i can do??? Also we have him tied up because he would wreck the house and when he crys my mom hits him so he can be quite i question he hitting all the time because i think its confusing the dog but she says she know whats shes doing i never had a dog so i dont know i just feel bad i dont like hearing the dog cry when he gets hit

can i get some real advice? i tell her him the dog away i feel that would be best because since my mom sleep for working night shift she dont never take him for walks nor play with him so the dog really doesnt plat all dog but she wont give him away......

so im a try my best to help train him so he wont get hit no more but idk he alwways thinks im playing when im being serious and i yell at him cuz he bites my hands and feet and it really hurts