How can you unlock an Iphone 6s without a home button?

My friend lend me his phone until mine was fixed. Since its his old phone, he doesn't remember the password and the home button doesn't work so I wouldn't be able to factory reset it. Is there anyway I can reset the phone? Would I have to take my friend to Apple to get it unlocked?

There's an on-screen Home button which can be enabled: Settings>Accessibilty>Assistive touch> On. Once active, if you press and hold the button then you can drag it to whichever bit of the screen you prefer.

But to do that you still need to unlock the phone using the PIN code.

If you haven't got that, and also access to the last owner's Apple username and Apple password then the phone will remain as useful as a brick.

If your friend has proof of purchase, rock solid proof of identity, and proof of his address then Apple can reset the phone and in doing so wipe it back to a blank phone, but there's also a fee for the service and your friend would have to pre-book an appointment to be seen at the Apple Genius Bar and turn in person. It's a big ask of someone who just wants to lend you his old phone.