Brother's step dad might have non consensually recorded a naked teenager with indoor security cameras?

I've never asked for advice here, I hope I've explained the situation clearly, if not I'm sorry. My step brother's (m16) step dad (his mom's husband) has had surveillance cameras installed within their house, which my brother noticed after his girlfriend (f17) walked naked in the kitchen and was probably recorded without her consent. Both my brother and his girlfriend were not told about the cameras. Said step dad has a history of erratic, creepy and dangerous behavior. He also self-admittedly frequently breaks laws and brags about it to my brother. Is there anything that can be done about the camera situation legally? We're all worried about the potential consequences of this man having footage of a naked teenager. Thank you for your help.