DCA is an effective strategy, it has a high probability of producing positive results in the long run, but there is no guarantee. Bitcoin is an investment that, if managed correctly, can have high long-term potential, but it is never guaranteed, and for this reason, you should not invest money that you cannot afford to lose, here you have to invest with the excess of your income, that is, you have to invest only that money that you do not need, no matter how small it is. There is no guarantee here, so investing with debt is never a good decision, so you should not lend him money, but rather advise him to invest with money that he can afford to lose.
There is no guarantee but based on all of our experiences, we're in profit if we've DCAed long time ago and we'll compare the price we have now.
And also the price when we're able to buy all of those Bitcoins in the past. But this is the right thing to do.
We shouldn't guarantee it to people that we talk to if we're discussing about Bitcoin. Because this is one of the craziest thing that they might do upon hearing that it's a guaranteed profit and that's to take a loan so they can invest.