Will he invest in the crypt, or open a deposit, or does it make sense to buy solid metal?
Saving with banks are the worst options among your suggestions, not only will your savings lose its value but you're also enriching another organization while you get nothing. Banks make use of our savings for their businesses and keep the profits for themselves. The best choices would be to buy an assets and they're many if them that'll help with preserving the value of your savings.
If you feel buying of Bitcoin is too risky then you can go into real estate, the value of a land or properties on that piece of land will always appreciate in value over time so your savings will be adding value instead of getting hit with inflation and that's what happens when you open a deposit with the banks.
Saving with banks is not necessarily as worst as you say. If you only have a small amount of money, then of course, saving in the bank is wasteful compared to investment. But if you have a very large amount of money, the profit from savings will be enough for you to spend your life. I have a wealthy uncle, he has more than $500,000 in savings, and he lives alone, and the interest he gets is enough for him to live without having to work in my country. And don't forget that billionaires with billions of dollars also have savings in the bank.
Moreover, savings can be used to deal with emergencies, not just for profit. As for me, I would diversify my assets, part savings, part investments to create more money.