If you're a long-term holder, you wouldn't have thoughts like the ones you're asking, that's why I see you're a short-term holder, you should first learn trading here in cryptocurrency while you do actual trading here.
It's really important that you have an idea and know how to read the chart on the graph so that at least you know where the price of bitcoin will go if it goes up or down? It's not good for a trader to depend your sales on what others say, it looks like you don't know what you're getting into and you don't know what to do.
What you say is very precise and I also really agree with the opinion you gave him where a trader is not advised to depend on other people's words or on what is said by other people other than his own knowledge. And it is also true that traders usually don't hold on long-term because they tend to sell when they see profits in the short term even though the profits are very meager. So it is very important for a trader to continue learning in terms of looking at price charts so that he has his own standard when he wants to sell something in the market.
I assume he is not a short term investor, or trader, he is someone who does not have much knowledge of the market but wants to get rich quickly from bitcoin, nothing more and nothing less. Because if he was a real investor and took the time to understand the market, he would never ask these questions. With a way of investing that does not research everything by himself but prefers to invest according to the advice of others, sooner or later, he will have to pay the price.