Welcome to PsychCentral!!!
I am 26 with bipolar 2 and have had struggles but slightly different than what your daughter is going through it seems. I managed to get my bachelors degree with little difficulty but when I started back for my Master's degree I have had to start and stop depending on my symptoms. I had to drop 2 courses one summer which cost me over $6000. On the other hand, I have managed to stick with my responsibilities at work and at home. I have lived on my own now for 5 years and haven't needed to be asking my family for help at all.
My point with this is everyone is different. My parents instilled in me very young the sense of responsibility. I had a pet to take care of 100% growing up, started working at 16, and was required to pay for my undergraduate degree because I didn't do well enough in high school. Even when Bipolar Disorder took effect when I was in a different state and away from my family, the one thing that always got me up and out of bed was my responsibilities to work and to keeping up my apartment. Your daughter may have different ideals and maybe she hasn't found that one thing in her life she needs to keep her motivated and moving in a positive direction forward.
I don't want to give you advice per se, but from my professional experience sometimes it works if you set more boundaries... for example, you decide what she needs to do for you to tolerate her behavior, maybe that's get a job working at least 20 hours per week, actively participate in therapy and take prescribed meds (you didn't mention if she's on meds or in therapy at this point). If it's important to you that she get a degree, maybe you want to set the limit that she has to take at least 1 class per term - I caution against this one only because Bipolar II often causes cognitive difficulties until stable so it may not be realistic that she can take a class right now. You don't mention possible substance abuse/alcoholism which is a different aspect as well. Basically it sounds like she's skating through life with you cleaning up the mess and it doesn't seem like that's working for either of you right now. She probably feels like crap and you may be experiencing frustration and anger and disappointment and other feelings related to her behavior. You're not unrealistic expecting her to get better necessarily. It is possible with the right limits and the right treatment. It's really hard work to get better but it is possible.
I truly wish you luck in dealing with this. It's a hard, hard situation that doesn't have a clear cut solution. I hope you don't take my posting the wrong way... I am just trying to show you the opposite side of the disorder where things are going decently. I believe she can turn things around. I also think she needs your help to do that, but she does have to own this and realize her responsibilities. She can't do that if you correct all her mistakes. Good luck and I wish you well. Post here as often as you need!!!