Bitcoin will be the best option to invest especially if you hodl for a long term. He can focus in Bitcoin and leave the altcoin while he use Bitcoin as his main investment. That will give him a big profit if he can accumulate Bitcoin using DCA.
If he want to invest in altcoin, he really need to be careful because a shitcoin are too many now. He may pick a wrong coin for his investment and make him lose the money. Not altcoin can work well for a long term because the market will delist the coin with no use. So it is why we need to pay attention to Bitcoin more than the other coins and accumulating it for a long term investment.
If it's the best then it is not an option. I do like Bitcoin but I'm not biased since I know that it had some flaws too. This makes others shine. Other coins are much stable and a good coin like that will always end up having a better value the longer you HODL them. Long-term investing is not hectic. It can allow us to have more choices.
We also have a saying that when Bitcoin rises others follow, so who doesn't want an extra money? In fact, we still can earn by the time Bitcoin dips, as some altcoins are also independent. Shitcoins are usually new coins, so if we are weak in research, then we can just stay on the older altcoins for us to be safe.