It depends on you and what you want otherwise putting it in a wallet is much far more better than that, putting in wallet as investment gives you more peace of heart and you would feel relaxed provided that you have the access to the wallet and store you seed phrase carefully then nothing to worry. But in future trading there is every possibility to lose it entirely without you counting about the money and will be gone.
Therefore, in my opinion I will advise you to go buy bitcoin and some reputable coin such as ETH, BNB TRX, DOGE and save the wait after halving till 2025 then you will never regret doing that.
If you advise only futures trading then I think you can advise him futures trading in bitcoin and small amount futures trading in ethereum. All other coins are not safe at all for futures trading and if the investor thinks that he will hold his futures trading for a long time then only Bitcoin will be safe for him. Bitcoin's market fluctuates within certain rules, not pumping up and dumping suddenly like other coins. Since there is not much volatility in the Bitcoin market, investors can trade Bitcoin futures with relatively low risk and continue their business for a long time.
If you are a newbie in this market, better not to go to futures yet. Be familiar with spot trading first and learn the ropes of crypto trading. It is quite to easy to liquidate your position if you don't know what you are getting into.