alt Hacker NewsGovernment-backed bonds are the intended zero-risk option. You know exactly how much you will get and it is designed to track inflation (sorta).
If you don't believe in that, precious metals are another way to go. I don't personally subscribe to that theory but that's the idea.
I think your parent's point is even larger than that. To be alive is to engage with risk. There are no stores of value that withstand all decay.