If your siblings already have that much debt with your parents as cosigners, it’s not even a foregone conclusion that your parents would continue to be approved for all of the Parent Plus loans you would need to finish at PSU.
All of the advice above is correct - withdraw from PSU after this semester. You have fine options in New Jersey; don’t take on crushing debt for no reason. It’s a blessing that you’re not in love with a school that you realistically cannot afford.