if it's an 18-year-old senior (or even a 17-year old), then it's time she learns to deal with "creepy" people in an adult manner.
It is ALWAYS OK to remove yourself from an uncomfortable situation or to communicate with others and to ask for help
It is always OK to not be forced into being “nice” to a creep, or to be subservient to one who is a male authority role, out of fear someone will think we are being silly, over emotional, or troublemakers
This child (vulnerable teen girl, no father figure) is already trying to deal with this teacher in an adult manner by talking to her mother, and suggesting ways to work with this man in a setting where she has the comfort level of others present being present.
Yet he is refusing.
That odd refusal to make any accommodation gets bad vibes from me. I would pull my child from the class and if necessary, the school
Do you have a teenage daughter? The willingness of a teenager to communicate this problem with a parent is a gift, and a cry for help. I would NEVER tell her to deal with a man giving her bad vibes on her own, much less leave her on her own with a high school teacher in power to give her failing grade for refusing to be totally alone with him and him insisting that she BE totally alone with him or fail