Keep your idea of DCA and never be tempted by other methods that can confuse you with the situation in the investment you are making.
You are sounding as if the other methods of bitcoin accumulation is a crime or they are something that are forbidden. Those other methods are there for bitcoin investors. He has started with DCA that's good and fine, but if it happens that money enters his hand and he decides to lump sum into his investment, I don't see anything bad in it. It depends on the circumstances he finds himself, if he chooses to utilise all the 3 methods of bitcoin investment I don't see anything wrong with it either.
You misunderstood. I'm not saying other ideas are evil or other strategies are evil but what I'm saying is it will confuse him, The reason is because this is the first purchase of btc he made and maybe DCA is very suitable to apply. So don't cut a line for you to conclude, you have to take many points that you have to align with the idea you want to express.
A beginner needs an approach with bitcoin, so dca is better because he continues to buy regularly. And in essence 2 months later he might be able to add another strategy if he is ready to live it.
Slowly people learn and there are many ways to buy Bitcoin. In other words, your income increases, then you are ready to budget more to invest in bitcoin. For example, previously budgeted 10% of course in the next stage it can be increased to 12% and that is because of the increase in income you get in that month.