This should be under the 'Bigfoot for Dummies' heading but since that doesn't exist, here we go. Does my BF have surge (inertia) brakes or full electric brakes?? Thanks!
What does the trailer currently have? Some will still have a 6 pin conector, some a 7 pin, but the 7 pin, even though almost no one uses the 7th pin (Back Up Lights) is current standard. And yes to the brake controller.
Sounds like he needs a 7 pin, but I would double check with what's actually on the trailer. A PO may have changed it to match an existing TV.'s receptacle.