What do youDO WHEN YOU BUY A PHONE USED FROM A FRIEND AND ITS STILL LOCKED

You'll need to know the username and password or the device will never be usable for you. Perhaps the family will follow: How to request access to a deceased family member's Apple account - Apple Support

Otherwise, recycle the device responsibly.

It is Activation Locked, a factory reset will not unlock it.

Chances are you won't be able to unlock it. If you can get a family member to take it to an Apple store with a death certificate, they may unlock it for you.

Read through the following article it says they can also help with unlocking their phone.

How to request access to a deceased family member's Apple account - Apple Support

You have to factory reset the device to be able to fully use it.