The jumper fits her it’s not too big at all. What is she wearing it with though looks like joggers? She looks a total scruff whatever they are. Even if it’s not professional dress in her work smart casual should be the bare minimum when you’re in a customer facing role and showing a bit of respect for the company. Midi skirt with a sweater and boots, long shirt dress over leggings, wrap dress, wide pants with a long cardi. There’s plenty of options for her size that will look presentable but comfortable.