At least, if he does not have many bitcoins, he can prepare his altcoins because the altcoin can get another altcoin season which will give a chance to the price to increase following bitcoin price. The popularity of bitcoin will grow and become a new trend which many people will see that finally, bitcoin price can surpass $100k and that will not stop that price from increasing more.
While the price is still below $50k, we still have time to buy but always analyze before buying to get bitcoin at a low price.
Altcoin season only happens after there is a huge bull run on bitcoin. I kind of figured it out by now but I can't give like some recipe for it because I could be wrong as well. I believe that after bitcoin reaches to a level where it is harder and requires a lot more money to go up, it stays there because it can't go any further up, spending another billion dollars on buying bitcoin more than selling, would only make people small return whereas if they start to put that back into altcoins, even if it is ethereum, then they could make a lot more profit.
We are not there right now, we could take bitcoin as high as 100k like the prediction OP made, however after that, altcoin season could start, or maybe before that, all I know is the fact that we would not be able to see something that is close to alt season until we see bitcoin rising a lot more than what it is right now.