I known lots of people who earn their living in a Casino. It is a matter of right strategy in every session I guess. I have talked to one of them and told me that it is a matter of discipline and planning when to quit. Though this person said that he does not win all the time but he is sure that he is raking profit in his career as a gambler.
Whoever told you that they could make a living out of a casino that has house edge in the games is lying. It is literally impossible mathematically to keep profiting. Even if you profit for 10 years, eventually all that 10 year will be lost one day since house edge ALWAYS takes your money back. If you decide to trust, well just go ahead and try yourself, put your money in there and keep working to make a living out of casinos and you will soon realize why I am saying that person was lying. There is no strategy, there is no mathematics, there is no methods, it is mathematically impossible.
To make it easier to understand let me say it like this, everyone says 2+2 equals 4 and your friend told you that "no sometimes it can be 5" and you believed that, just don't.