If Bernie wins, how much will he REALLY be able to change?

If you see false statements or a stupid question its probably because my lack of knowledge. Enlighten me, that's why I'm here!

"Too big to fail" - If Sanders wins, will he be able to change the system for the better. E.g will he be able to prohibit companies from having so much influence on politics etc?

"Free" collage tuition/healthcare, I know this is possible. But how likely is it?

Edit: Thank you for answering my questions, I appreciate it! Good luck in the upcoming election