Thanks for your question! I think I’d begin by asking the person a few questions:
(1) What do they mean by “religion”?
(2) What do they mean by “mind control”?
(3) What about non-religious “mind control” — advertising, politics, even secularism?
(4) How can they be sure their own mind is free of influences etc.?
As we chatted around that, I’d want to introduce to them the idea that, for sure, there are lots of attempts to manipulate people — usually the powerful attempting to influence/manipulate the weak. And, yes, religion can be used this way. But when you look in the gospels, we see this was a major critique Jesus had of religion — look how he attacks the Pharisees for trying to control people etc.
So, for sure there’s “bad religion”. But one might ask your friend: could there be genuine religious faith — that sets you free, rather than locks you in and manipulates you?
A book I’d try to steer them toward is my friend Bruxy Cavey’s book, The End of Religion.
Hope some of that helps?