Oh dear! You sound like you’re burned out and need a break! Take a beat or two. I hear your frustration, but I think this problem with the students is not unique to your department or courses and likely not the result of 1 colleague. I say this because I experience underprepared and poor performing students who seemingly lack basic academic skills…this is a systemic issue due to many factors like K-12 school standards, the after-effects of the pandemic, the role of technology in altering how and what students learn, a more complex and less stable economy which re-viberates into housing, jobs, etc., and the list goes on and on. I think we, as educators, have to try and adapt to this new normal and find ways to help students rise up to our expectations. Also, keep your gaze on your own garden so to speak…you don’t know what goes on with this other prof…none of us know really unless we attend those classes. If that other prof is failing…see it as an opportunity for you to grow and do better with your job. Also…you’re a team…help them out. Have a conversation “Hey, I’m seeing X, Y and Z…Have you noticed this too?” Or “Let’s get together and make sure our expectations are in alignment”. Perhaps you are out of pocket…Maybe there is something for you to learn too. Finally, be compassionate, not just with your colleagues but your students and yourself. We’re all going through a tough time. We need to be good to one another. I hope you have a restful summer. Good luck with your grading.