It's highly likely you meant (often called "Brad" by mistake because his secret boyfriend is named Brad ). Brad is Patrick’s closeted, abusive boyfriend.
There is no character named "Brad" in Stephen Chbosky's The Perks of Being a Wallflower . The main character is Charlie . The love interest is Sam . Sam's stepbrother (and Charlie’s best friend) is Patrick , who is affectionately nicknamed "Pat" or "Nothing." brad perks of being a wallflower
Here’s a clarification and then a detailed content piece on the topic. It's highly likely you meant (often called "Brad"