If she had absolutely no tension on top she would be having more problems than eyelashing on the bobbin side. How does the machine sew for piecing and not FMQ? If it is sewing fine for piecing she has good tension. BTW most machines have no upper tension when the presser foot is raised and we usually thread our machines the presser foot is up.
If the machine's tension is ok when piecing then the problem of eyelashing can be addressed by decreasing bobbin tension, or increasing upper tension and slowing down for curves.