First, I strongly believe we should listen to our parents.
However, as I am sure many people on here will tell you, a pigeon with a broken leg is a relatively common occurrence. And it is a minor injury. If left alone it will heal by itself in just a few weeks. You can buy leg splints for pigeons. If you don't already have one to use the leg may be partly healed until you get one. I recommend getting one for next time. The bird will still be able to eat, fly, and take care of itself.
And you might want to respectfully share the comments on here with your father and ask him to consider waiting a few weeks to see how it heals.