I'm going to tell my grandma she has no legal rights
Why would you say this? What would motivate you to tell your grandma that she has no rights?
I'm furious because she put me down all the time about my drunken nights
Your grandma does have legal rights, so what you are saying is a lie. Don't lie to your grandma or she will end up cutting you off.
I'm not saying it's true.I'm just mad. I can't wait to disappoint her when she come over again.
You shouldn't tell lies just because you are mad. Lies will make your life complicated because they are hard to remember.