Can a Teacher Be Fired for Asking a Student Where or How to Purchase Cocaine?

A teacher I work with checked herself into a drug treatment center to get help for cocaine addiction. While she was out on a medical leave, a student stepped forward and admitted that the teacher came to her and asked if she knew where or how she could get her hands on some cocaine. Unfortunately, I know this to be true because the teacher herself told me about her cocaine problem and that she had solicited drugs from that student. From what I am told, it is illegal to fire a person for having a substance abuse problem if they seek help on their own. However, I would like to know if asking a student changes that. I like this co-worker and I am glad she is seeking help, but I am very upset with her for involving a student. Furthermore, I am upset that our school and the teachers’ union are protecting her. Can the union keep her from getting fired?