I have a project manager who's managing a sizable project (8 developers, duration over 6 months) with rapidly and constantly changing requirements. The PM has started dumping hundreds of tickets into the 2-week sprint a couple of sprints back, and given that it's impossible to finish that much work, he just adds new tickets on top of the existing ones, and moves everything to the next sprint.
I demanded that clean up the sprint board, and move anything not being worked on to the backlog, but he started arguing that although that sounds nice, he and his team don't have time to move things in and out, as the requirements change daily. He said that they know how to prioritize the tickets in the system without moving them in and out of the sprint.
How can I convince him to change his ways? I told him that with the current setup, it's almost impossible to track velocity and for devs to track what they've worked on, and he claims that they know exactly what they're working on and if we wanted to find out the velocity we can generate a report based on the finished tickets at the end of the sprint.
Any ideas for/against are welcome.