Thanks for these valuables series..I think that to counteract brainwashing, you should be:

A strong personal belief system
Fearless self assurance
Self knowledge
Taking an active role in caring for yourself
Asking questions
Seek evidence
Be honest
Teach, don’t preach
Remember there is a difference between teaching and brainwashing. Brainwashing always involves an element of coercion. Teaching is compassionate guidance towards the truth. I think that the best way to protect someone you love from the effects of brainwashing, would be to help them to practice and develop the things listed here.