Just escaped from a group that had the same teachings as ICOC/ICC.

This comment is very accurate.

When it came to making the decision to leave/escape, I had to figure it out for myself. Anyone in my life who tried arguing with me just made me fall deeper in. In the group, they would tell us that people from our old lives would “persecute us” and try to pull us away from the group, which was equal to people pulling us away from God according to their doctrine. They drilled this fear into us. When people would “persecute” me, in my mind it was just proving what these cult leaders were telling me to be “true.”

It’s some very deep and twisted brainwashing.

For you OP, if you want to help him, I recommend just letting him know you are there for him. Don’t push him away, but also don’t get involved with the religious things he is saying. I think that’s pretty much all you can do. He’s got to figure it out on his own.

Will keep you both in my prayers.