Unlock my samsung j7 phone with out google account.

My small brother has attempt wrong password for many time and now it askes for google account which I don't know. I am talking about samsung j7. I have tried factory data reset and reboot but after the start with "choosing language option" and "agree terms and condition" it asks for google account which I don't know. How can I make my phone in useful mode.(starting mode).? help please