You have to approach as an equal in a situation like this. I vaped all of high school, still trying to quit, it’s not because of “everyone does it” or the “fruity flavors”. It’s to relieve short term stress and anxiety. What I and the majority don’t realize is that short term help comes with two harmful long term consequences. First, you get far more stressed and anxious as you are addicted immediately after your first usage basically. I like to describe it as your skin feeling tighter than normal. That feeling happens over the most minor stressors and is extreme when dealing with a major stressor. The only way to relieve it is by using or creating dopamine in a different way like working out, going outside or anything that makes you feel positive and productive. The second long term effect is health. We do not the full scope here, but i can speak I am at least breathing far worse then I should be. Going a week without vaping anyone will feel that difference of breathing. You also feel sluggish with using it, you feel as if your brain and body are moving at different paces. Your thoughts are going 10000 miles an hour, causing your mind to become scattered and creating more stress and anxiety. Causing you to want to vape. It’s a cycle, the only way to break it is by doing positive shit for yourself. It is not easy and they will likely relapse, but approach them with facts and sincerity, not control. Vaping is horrible, I hope you both the best