some times I did see it make a profit, and some times it didn't.
I think this entirely encapsulates gambling in a nutshell- sometimes we win and sometimes we lose. This strategy and pattern that your friend noticed is just something that he rationalizes. While we often associate randomness to a pattern, we must fully understand that gambling is all about luck.
However, I wasn't focused on what he was doing; I felt it was all about luck, so personally, I just played slots without paying attention to any particular patterns. So, what about you? Are you one of those people? or are you just a casual player like me? If so, please give your reasons.
It is definitely luck. If there is an exploit that will guarantee you a win on your slots by observing that pattern, then the gambling casino would notice it and fix such issue. Additionally, that person would NEVER share that exploit to someone.