I haven't yet read all the posts but I'll state some general interpreting principles.
Interpreters should not discuss other interpreters with clients.
Interpreters should not sleep in front of clients. If the terp is working extended shifts and needs to sleep then go to a break room or elsewhere but be available to paging or have another terp stand-by.
Interpreters should not be "explaining" medical procedures outside the presence of medical staff. If more explanation beyond normal expansion is required, then the terp turns to the medical professional and says either, "Interpreter needs more detailed description" or "Patient requests more details," depending on which fits the situation. Interpreters should not answer medical questions. Interpreters who are left alone with patients should say, "Let me get a nurse/doctor and you can ask them." If the doctor/nurse asks the terp to "tell" the patient to do something, or to ask the patient something without directly addressing the patient (like while the patient is asleep or in the bathroom), the terp should say, "I'll be happy to interpret your question or orders for you when the patient returns." (Use professional tone but smile pleasantly.)
Technically, the terp is supposed to wait outside the hospital room until both parties, hearing and deaf, are present. Practically, depending on patient preferences, the terp "hangs out" in the hospital room for long assignments that include lots of gaps in actual signing times. If the patient requests the terp stay in the room, that's fine. If not, then the terp steps outside until needed. In the South, there seems to be more tendency for patients to want the terp to stay and chat. As long as the chat topic guidelines are followed, that's fine. No gossip about other terps or deaf people!
A deaf patient or family member has enough to worry about without having to report an inadequate terp to authorities. Ideally, someone from the staff who does the terp hiring should check in with the patient after the terp leaves to get feedback. Just a brief visit, asking the patient, were you satisfied with the terp service? (Maybe a short, simple feedback form for terp services.) If there are any problems, the hospital to resolve them. I realize that's the ideal and may not be possible in every situation.
If you have to complain, do it but not to another terp. Tell the desk nurse or doctor.