What is the ruling of Sharia on the conduct of a father who bypasses the bread queue at the invitation of the bakery owner — who offers him this privilege due to the father's position and the latter's efforts in fulfilling people's needs — and what is the ruling on that for each of the father, the bakery owner, and the questioning daughter who sees this as an infringement on people's rights, and the people standing in the queue?

Your father's transgression of bypassing the queue is an infringement upon the rights of those who preceded him, and he is unjust towards them. Therefore, the baker's permission is of no value because it comes from someone who does not possess the right, and he is complicit with your father in sin. The baker's offering preferential treatment to your father in order to favor his daughter might be a forbidden bribe. If you have advised your father and denounced his action, then you have fulfilled your obligation, and nothing more is required of you, nor is there any sin upon you for what he does.