Actually it is. People ALREADY know the unpleasant truth so telling them this is just adding a layer of your own frustration on them, a layer that they do not need. Same from people who are in denial. Usually, people in denial are there for a very good reason. If you want to unlock this, understand their lives, but do not tell them "the harsh truth", its simply unproductive and you will only gain distrust from that.
Again, people fight their own battle. Telling "the harsh truth" is just an excuse to avoid saying "I'm telling this person my frustration of seeing them unwell"
You want to support ? Love, stay close and trust.
Well, I hope you have good relationships with your family.
When someone is in difficulty, its important to show support an even the balance. So when someone really feel like they are unworthy of living because of their physic, mental illness, addiction or financial situation, telling them that they are perfect the way they are is absolutely VITAL to restore the balance. Even if technically, perfection means the absence of bad.