He cannot however know nor see any event that doesn't happen. This is not an arbitrary limit on God: this is simply logic; omniscience properly understood.
In the same way that God is omnipotent but cannot make 1+1=3, so it is with omniscience. He cannot know an event that never happened.
Let us try a reductio ad absurdum thought-experiment which may make this clearer.
Eric fathers a child and is presented with the temptation or opportunity to get rid of that child.
He chooses to kill the child.
God sees Eric's whole life, the choice and the act of murder. Moreover He sees it from outside of Time and Space, certainly before Eric commits the deed.
Pretend for a moment that God can/will roll back His creation of Eric. There is no abortion, no murder.
Or alternatively pretend for a moment that God can/will roll back Eric's fathering of that child. Again: there is no abortion, no murder.
In either case: that act of abortion has never existed. Either the choice never existed, or Eric never existed.
Here's the punchline. How did God see that act of abortion? What act of abortion? It never existed.
We would be left with the absurd picture of God being unable to see/know things that He Himself has seen/known, because He Himself had undone them.
God knows what Eric's choice will be before time, because that moment of choice happens and He knows the result.
But He cannot know what Eric would have chosen if Eric was somehow never presented with that choice.
This sort of discussion is a very necessary part of the 'problem of evil' - or 'Why does God allow evil to exist?'
One part of the answer is because our good and evil choices cannot be known unless they are allowed to occur.
And also because God creates us once: He does not (for instance) maintain parallel Universes containing different versions of us with different choices, like a tired Star Trek trope.
Hope this was helpful. Very stimulating conversation BTW.
ok thanks, I personally do not believe that God is limited to what we see as logical.