It really does fall on the instructor or the "enablers" to deal with the situation. When I was an instructor and a mentor I had to learn there are these people in every class. So when they interrupt, if I am in the middle of a training there is a chance someone else has the same question so answer the question as best I could. If we were is a part that required them to do something, I would walk around and see if anyone needed assistance. In a sewing situation and a person has to un-sew, then I would say I will be back when you have finished taking out what needed to be undone, just raise your hand so I know when you are ready. It took me a while to learn to instruct and not do for someone. If people are doing it for her, then she won't learn. If she asks someone to do it for her then they need to say no - she has to do it in order to learn.
No one needs to be rude, they just need to instruct rather than do for her. Once she finds out no one is going to do it for her, she will either leave or learn to do it herself. If you are not the instructor, then direct her to the instructor for assistance. She may have to wait but again, she will learn or leave.