Forgotten pattern password

So I've forgot my pattern password and thought I could unlock it using my google password, I've had 100 retries and still no option to unlock using my google password. What can I do to unlock my phone will I never get the option to unlock it using my google password? Using lollipop as well, does lollipop not have the google password unlock feature?

my grandson has forgotten his password for his old samsung any idea how to unlock it

it is a galaxy -y