My mate's youngest daughter has anxiety and depression issues.

She continually makes poor decisions but no one can tell her anything. Always has a need, need, need, want, want, want, me, me, me disposition.

If things don't go the way she hopes they will she becomes impossible to be around.

Takes a lot of energy to be around her.

How do I learn to just let things go and not worry about her and her and the poor decisions she makes?

Thanks.