What is the ruling on eating, drinking, clothing, and university expenses from the trust money from which the family spends, and is it obligatory to boycott food and refuse to take from them, knowing that breaking the fast for an expiatory oath is done from this money?

It is not permissible to dispose of a trust without the permission of its owner. Therefore, your family's disposal of the trust without the owner's permission is forbidden (haram). You are not permitted to accept anything from it except in cases of extreme necessity. You must seek another source of livelihood or obtain the permission of the trust's owner.