I do not agree that a person who is not healthy cannot advise another. You can advise when you can, if it really comes from the heart. Not in a hypocritical way. No one knows the reason for a person's addiction.
They have done many studies on the incidence of cancer in young people who use vapers. Perhaps it is too early for the majority of those in power to accept the results provided by independent and isolated studies, but what is certain is that deaths from respiratory diseases have increased, no one can deny it.
The result of technology is exposure to radiation that is imperceptible to humans but that the body does capture, sensitize, attack, colonize and unleash diseases that we do not even suspect of the origin. Cell phones, electronics, electrical devices, etc. They all have compounds that are harmful to humans in the long run.
I live near oil refineries, it helps me that I am close to the sea, rivers and a lot of vegetation, but the refineries gradually contaminate the environment and the long-term consequences are terrible. But economic power is in charge.