First of all, thank you all for such helpful responses! After reading all your comments, I’m overwhelmed by the responses but also other considerations for my younger sister.
Second, to address your questions (especially to helpful @thumper1 @Sybylla)
- I'm not her legal guardian. I have simply taken over her education decisions since my parents are non-English speakers and retired.
- My parents will be moving along with my younger sister. My mom is the original green card applicant therefore, my sister and I benefit from her status. Ideally, we would try to bring our dad as well.
- In terms of finances, my parents are relying on their passive income and savings to pay for housing and other living expenses. However, my parents are quite old (they had my younger sister in their early 40s) and would take care of my younger sister. We have calculated our options but still figuring out what to do for my younger's sister college. While we are trying to find a situation fitting for my younger sister, my parents are still prescribed to Ivy leagues or prestigious schools = best colleges.
- As of myself, I am currently looking for a role in the States. I used to work in California but then left to handle some of the family business. Once my sister returns to the States, I will find a job out there as a UX designer. Since I only have a boyfriend (Australia), I'm quite flexible on locations)
*also please ignore my comment above - it was my failed attempt to try to edit the answer