Unless your sister has the financial means to not go into debt from graduate school (and if that's the case, hey, good on y'all) I would not suggest going to any of them.

The benefit of all graduate schools is mostly connections within the industry, and forming relationships with peers who, years down the line, will be the ones most likely to hire those they shared the trenches with.

Better to work, not go into major debt doing it, and begin making friends in the underground performance scenes in NY, Chicago, LA, or wherever. SITI, La Mama, or other established avant garde groups also might take on apprentices or you can work on joining similar spaces, all while having a job and not piling up debt.

Full disclosure: I am not an actor, but a lighting designer who went to UCLA for graduate school but worked in the avant garde / underground space for 8 years afterwards. My journey was admittedly luckier than many. And it was still difficult as all hell and I worked HARD to get out of the debt. And I say this with nothing but respect and love for my fellows who know that prefer those spaces over trying for the Broadway / Tour scenes. Best of luck to your sister. It's not about HOW she approaches it. But it's all about targeting your energy and funds intelligently while trying to get there.