There are often times when people you care about will make decisions you don’t understand. From your point of view, one side is nothing but milk and honey and the other side is possibly not even a good thing. Maybe they’d rather walk around sick for weeks instead of visiting a doctor and getting cured today. Maybe they’d rather return to something in their past instead of being in the present.
Instead of trying to control, instead of letting them know all the reasons why the other way is better in your opinion, relate by finding out their feelings, and let them decide. The truth is that even if they elaborate completely, you don’t know what the decision truly is they’re faced with. You only know what you’ve heard through your context.
Very few decisions are permanent. Maybe they’ll go to the doctor next week after it gets worse. Maybe they’ll spend one week in the past before they realize it was the wrong decision. You never know exactly what led to their decisions, the only thing you can know for sure is that trying to control the situation yourself is not the way to go.
Relate, do not control. It’s the best thing in the long run.