if it is a game that relies on luck, no matter what strategy he uses to win, then the result will still be the same that the casino will win, because from the beginning the casino uses an algorithm that makes it more profitable than the players. if your friend understands the algorithm and house edge, then he should understand this and stop using the patterns he believes in to win because it is indeed useless at all.
While I agree with what you say about gambling and the actual uselessness of strategies, we must understand and important factor and that is why so many gamblers fall into the illusion of believing they found a "pattern" or strategy which will indefinitely work for them to get money from the casino: naturally each human being is biologically adapted to identity patterns and use them for survival and improvement. That is what many of the scientific knowledge is based upon, actually.
The only branch of science which does not apply to the following of patterns is statistics, the Gauss distribution of chances is the only pattern which could be applied on gambling and yet, it cannot be used to abuse the probalities, only can be used to understand the chances one has to earn or lose money based on the multipliers and the number of sessions, dice rolls, slot spins, etc...
So even though I try to tell people to stay away from false patterns, I cannot blame them for seeing them, as it is part of human nature to try to do so.