Bringing a minor across border

Hey all! I’d like to take my 12 year old brother across the border for a camping trip in Nova Scotia, probably through ME or NY. Our parents are separated but not yet legally divorced

What documents will I need to get him through since he’s a minor? Ideally I would not want to ask for anything from our father, our relationship is strained. But for this trip, I would if necessary.

TYIA!