A problem with the term 'fear of failure' is that it's not necessarily fear so much as simply a prudent worry that you might possibly or very probably be utterly wasting your time. If someone tries to help you and says that essentially you're afraid, people can respond as if you're criticizing them. (You're just afraid! Grow some balls!") And people who feel they're being criticized are less likely to listen.

If someone is causing harm (including to themselves) or in any case where the direction a person is taking does not appear to be the optimum, the thing to do is manage to tell them a better way and/or tell them what they're doing wrong while somehow managing to not sound as if you're criticizing them. Which you are.