Please don't delete the thread, we are all concerned with your wellfare and Shae's wellbeing as well. Is the dog safe with you and your mom now?

Hopefully your step-brother has had a counselor or someone talk to him. Even if he was "kidding" this is abusive behavior. If your step-mother was watching, and did not intervene on your behalf, or the dog's behalf, she has no right to be angry at your, or at the dog. But the dog cannot stay with her any more.

Again, is the dog, Shae, with you and your mom now?