This idea that we have to respect other people's decisions is so stupid. There is nothing in the world wrong with believing that someone else is making a mistake. We have brains so we can make these sorts of judgements.
But it would be wiser to base it on empathy and understanding than ego.
Agreed, but you need to keep it on a leash, or it will ruin your life.
I know more about the situation and you do, the person question is a relative I care for deeply.