Wish she'd wait a little longer

I come from an old school family and my sister has anorexia bulimia that was diagnosed in the spring. She's been at a facility all summer getting treatment and my parents are pushing for her to take a gap year and continue treatment as she only recently became bulimic at college. Seems like the restrictive eating has been going on longer, and shockingly to all of us, the suicidal thoughts have been on and off for several years.

Mom and Dad have been strong in their stance that she should concentrate on herself and take a gap semester or two, but she is standing fast that she is returning to college. She recently told them that is her final answer because college is the only place that makes her happy. Even though that is where her bulimia started. What's scary though is that over the last x weeks it doesn't seem like the facility has given her enough tools yet to go back to "normal" life, instead they boxed her in and turned off all the noise so she wasn't overstimulated/triggered, and she has only just started to have a little freedom, but has yet to learn how to healthily handle exercise, the mental load, and good eating habits amongst the day to day noise.

I love her and I'm scared her relapse will be more prevalent at college as she's going for a hard degree. Our family doesn't come from money to continuously support her getting the care she needs.

My parents really love her, but they're very hurt that she's choosing to put everything she's gained over the last 2.5 months at risk. I don't know if my parents will be able to support this decision as they know this is a long road and want to give her the best shot, especially while all the resources and time are available. I personally don't support this decision either, but I love her and am trying to be open minded .

I guess, is there anything else we can say or do to get her to really confirm she feels confident that she can handle the stress of school and life? How do we know it's not her ED talking? She says it's not....And if not how can I support her from afar? Ex. I've read about virtual meals, but not sure my schedule will allow the flexibility to meet often at those times. Or how do I support her when she stumbles because she wanted to immerse herself in the fun option?

Appreciate your help and guidance.