At this point the person is cornered and not being reasonable.
You may choose to continue the dialogue,
but I suggest ending it here by pasting...

I fail to see how the possibility of God existing not being an alternative when ALL FACTS cannot be known (by you or anyone). That seems unreasonable...

and illogical. We'll just have to agree to disagree on this one. Thanks for the time you took in answering my questions. Take care and God bless.

If the person finally admits that it's an opinion, go here.