“The father may have had no way of knowing that, but we do.”
WE don’t count.
Sure we do, as we are the ones discussing the case here. You can’t simply assert “he was an intruder” when we all can see that is factually false.
You could say “the father thought he was an intruder” and that would be fine, but to say “he was an intruder” is a demonstrably false statement.