I'm going to tell my mom about the vape I found in my brother's room
You seem to be very determined with this. What do you hope will happen if you tell your mom?
I want to get my brother in trouble and make sure he will never smoke pot again.
It's good that you want to protect your brother. However, you will lose your brothers trust if you tell on him. Instead, you should talk to your brother about the consequences of his actions.
I don't care if my brother doesn't trust me.
I think I recommend you to care about what your brother thinks of you. He should see you as someone he can trust and love, as he may not have that much people in his life that he can trust and love and without you being trusted, he may have a hard life ahead of him and he will suffer. I do hope you reconsider this and hope you will care for your brother.