At ge 26…she is too old for you to get onto treatment unless she was declared incompetent. That does not sound like the case.
Unfortunately…she has some issues to deal with.
Fortunately, you aren’t paying her bills.
Have you ever sought any counseling to deal with this situation? Your other kids are high achieving! Ivy League level students who sound like they are on track to graduate on time.
When I read your back posts…I remembered your story. This isn’t new.