I'm infuriated with my father for spending my grandfather's will money on a hot tub when he constantly complains about bills to pay for the family
Why do you think he would do something like that?
He never cared about family life or his kids, he just cares about himself.
I'm sorry this is happening in your family. He should definitely priorities bills about luxuries like hot tubs especially if he's going to complain about said bills. Have you tried talking to him?
I'm too furious to speak to him. I think I'm going to kill him and blame it on my mom.
I hope you're joking, because killing your father would be a gross overreaction. Harming your family members is not only wrong, but it can also lead to you getting an a lot of legal trouble. I know you're upset with your father, but I think you need to take some time to cool down and then talk to him later.