Professor Isn't responding? MSW

[gk8]

I have asked a professor to do my recommendation letters. I told him in late October and he agreed. I have gone to see him a few times  in his office hours and he has said that he was going to work on them.  He has not done any of them as of now. I have emailed him, called him, gone to his office hours and he is not there.  I am currently volunteering at a hospital and have already asked my manager to be one of my recommenders. There is another manager or coordinator in the same hospital that I also work with. They are basically coworkers. Would it be okay for her to be one of my references even though she works in the same hospital and almost has the same title as my other reference. Thank you.