Reply To: Do I give money to my siblings from an apartment in my and my sister’s name?

A few more thoughts:
You aren’t obligated to discuss this with your parents at all, period. “Mom and dad, I’m struggling with the decisions you’ve made that have put all of us paying for college on our own despite your own promises and money that was set aside by Grandma. I’m not comfortable discussing the apartment sale with you as a result. What you need to know is that you should plan (or not plan) to invest in our siblings’ college funds because we will not be paying for them. That’s your responsibility, not ours. What we’re doing with the apartment money is for us to decide and I need this matter to be closed. If you insist on bringing it up again we’ll have to end the conversation there.”

You should talk transparently with your younger siblings about the reality that they cannot trust your parents and they’re going to need to plan to pay 100% for college themselves. You should also prepare for your parents to tell the younger siblings you “kept” money meant for their education – which would be a very cruel move, and I hope they don’t, but it’s possible. They need to know about the rent money and work as hard as possible to get as many scholarships as they can.