I think that if a witness was having doubts, then the pyramid and other such nonsense would strike a cord, otherwise it is not a big deal. My brother and his family are kool-aid drinkers and NOTHING changes their perceptions.
Overwhelming biblical examples that explicitly counter WTS positions and teachings mean nothing. Examples of blatant lies and twisting of words and scriptures mean nothing. Even proof of the church fathers' teachings that prove that EVERYONE OF THEM believed Jesus was God in the flesh mean nothing.
One time only as my brother was rambling on about 'you know a tree by it's fruits' and I asked 'What fruits?" And he gave the standard line about going door to door restoring the true name of God, yaddayadda. And I informed him that these things are works, not fruits. He was perplexed for 2 days and when we spoke about the fruits again, he stated that works are fruits. How can you reason when you have no common sense and reasoning?