He have good full time job as software engineering (5 years experience).
He begin side hustle. He join a real estate agency. (which seem unreasonable because he should work in IT industry side hustle, which he have 5 years experience) But most of the time he taking class, and post picture of class on social media.
I am worries. It feel like a cult.
You may want to give us some more details. It sounds like your friend is taking a course about real estate, but so far I don’t see why these people are a cult.
If you can explain to me why they are a cult, then you can also explain it to your friend, and that’s a good first step to get them out.
If he needs to pay the real estate business to get started and if he needs to recruit other people, it is likely MLM (pyramid scheme). There is a database of those here.
Real estate is where the money is.
Really depends on the type of class, etc. It sounds pretty benign the way you describe it.