If my rat has cancer and my parents refuse to take it to the vet what can i do to get them to take her?

I found a tumor on my rats side twards the shoulder. And ive been begging my mom and dad to take her (sniffy) to the vet. But my mom is litterally mentally unfit and shes not the smartest person She says sniffy will get better and my dads a drunk so hes always mean and he just wont take her. And her tumor is getting bigger and bigger. What can i do to get them to take her to the vet. Ive cried my eyes out begging them. Ive cleaned the whole house. Ive even gave them 100 dollers to take her. My dad took the 100 and bought beer, gas for the car, and a new muffler. Can i call the animal police people and tell them about my parents and how there not taking sniffy? But i really love sniffy with all my heart. and shes my best friend! And lets just say my family is mentally messed up, and i have a major depression problem (yes i have counciling and i take meds) bit i am severly depressed all the time and if sniffy dosent make it then i might not either if you get what im saying. Thats how much i love her. and nothing can replace her! What do i do to get them to take her!? Please help!