I can’t give you legal advice, but a similar thing happened to my mother.

She had a very rough childhood due to the fact that my grandpa was an international business man who was never home, and my grandmother was abusive and crazy.

My grandpa left my mom and my brother over $500,000 each, to be used in part for college, and then to be given in whole once they had received their diplomas.

This was basically all of my grandpas money, however after he had passed and before my mom and uncle attended college, my grandmother somehow accessed all of it.

To this day nobody knows what happened to the money.

Both my mom and brother attended college and graduated with heavy student debts. They were furious when they found out what happened in the years after, however my grandmother was already financially unstable. Nothing could be done at that point.