Doctors in Macbeth

Doctors in the play seem to do little to nothing, with them only have two appearances and only observing what is going on. in the last act, a doctor comes and witnesses the extent of Lady Macbeth's guilt and what it is causing her to do. In act 5 we see that Lady Macbeth sleepwalks and talks about what she knows about the murder of Duncan and Banquo, and yet another character appears to do nothing about it. What could have been done by the doctor anyways? Lady Macbeth seemed like she was extremely bad and full of guilt, not like they can confront the king and her about it... unless they wanted to get killed.