Bad airline

Recently, my sisters and I took a short trip to scatter our mother's ashes. The problem arose upon our return home where we were told that the flight is overbooked and one of us would need to be on standby. Both my sisters have comorbidities, so it was essential that we fly together. This was a completely infuriating experience - especially when the check-in clerk instructed us to "CALM DOWN". How can an airline overbook each flight? That's not fair at all!!! Yes, my sisters and are adults, but would you separate a mother and child flying together??? Who has the power to decide who must board and then be on standby after paying and exorbitant amount of money for the tickets??? It's absolutely ridiculous that some of our money is still held captive and forces us to fly with a badly managed airline. Management needs to catch a wake up!!! Your "frontline" workers deserve better leaders.