There's a lot more to marketing than telemarketing. Sounds like she is thinking a little too small here. Are you in a small town? As MrsDinero suggested, there are a lot of great jobs in marketing. In many different fields. She could work in marketing for an arts theatre or something.
She should absolutely teach dance as a side gig. Or, could she use her marketing degree and sales experience to open a dance studio? She'd likely have a leg up (pun totally intended) on other new dance instructors given she (should) understand how business works.