@mrnephew, was this truly a decision that you were entitled to make that was potentially being made for you?
Or, perhaps, going to boarding school was a new possibility in your life that did not have to happen. That you are able to be at a boarding school- is that a gift? Or is the selection among boarding schools a selection you are entitled to make, since (you believe) it affects your life most directly?
I am simply pointing out that sending a child to boarding school affect the lives of family members-including siblings- very directly, and perhaps the head of the family is entitled to make the decision of which, if any, school shall be chosen. Hopefully that is done after weighing the effect on all members of the family; but the head of the family may choose to weight his/her own self interest more than that of the children. This is a major life decision in the life of the family, as well as in the lives of each if its members.
Being able to attend boarding school is a gift, not an entitlement. As with most gifts, it is not your choice what you are given.
That is true for you as well as for the OP.