Will he invest in the crypt, or open a deposit, or does it make sense to buy solid metal?
All of it makes sense.
You still save some cash, you save/invest in crypto but mainly in bitcoin and then if you can still afford to buy precious/solid metals then do all of it.
Those are good choices IMO but then you have to prioritize what you think should have the most of your fund and this is just like diversifying your wealth then.