Activation lock on IPhone 6S

I have a IPhone 6S from a friend saying he can't open it, which resulted to be a locked iCloud account the IMEI which was not blacklisted. He says that the previous owner does not want to unlock it and when I contacted him he said that he forgot his password. So I told him he could change it but he said it was too much of a hassle. Is there any way to unlock it since the previous owner does not want to comply to unlocking it.

-Thank you