We can’t force them on what to do especially on a bear market like this but of course they should always go for the basic strategy which is to but low and sell high since this is the only way to make profit. If in doubt, keep learning and you can really know when to buy and sell, this can be more an easy decision for you once you learned it.
It's good to see they are struggling at some point so that they will realized that investing crypto is not that simple. Many thinks that crypto is easy money during the bull trend. Seeing their assets now decreasing the value, they will end up frustrated and will do something to cover their loss.
There's no perfect investment hence there's no perfect strategy. We need to be wise at any given trend.