For this reason, we have suggested buying bitcoins when market conditions are declining today because the potential for bitcoin to increase is very high. If he still wants to choose altcoins and focus on altcoins, we must be extra careful in choosing the coins. Not all altcoins will increase. Even altcoins are currently in the top positions. And if bitcoin declines further, they will have to be very patient to wait for a price reversal.
Investing into bitcoin is always far better, this is about if you already have some alts, but if I had some cash and no coins then I would pick bitcoin over anything else that part is true.
If we are talking about the aftermath, like I already own alts and they are down, then we can discuss how buying more to do DCA could work or you just accept the loss and move on, because in that situation there is no selling those and getting BTC considering it would not make sense to accept the loss by selling, it's better to wait it out and see how it would work. I know that it's going to end up with a bit of a problem in the long run but it will also not be something that may result the same way for all coins.