Things You'd Like To Tell Visitors . . . . and get away with it

In my experience the type of reactions from relatives you are describing are caused by fear and feeling inadequate - as is most bluster, anger, etc. I can see that you are really upset by it, but don't retaliate because it will only escalate the problem (and make you feel worse). Take control rather than buy-in. Here's how: try to defuse their fear: give them your full attention - eye to eye; stop what you're doing, listen wholeheartedly to them and respond to their feelings not their words; calmly paraphrase back to them as a question to show you have understood/are listening and to clarify your understanding - (part of their frustration and fear has to do with the fact that nobody is listening to them); give them an answer that explains/clarifies/clears their confusion and offer them an alternative solution (for example - "I can't give your mum more pain meds right now because it would be dangerous and might stop her from breathing. I know you want to help her and I can see how upset you are that she is hurting. You can help her right now by distracting her from the pain. Massaging lotion into her hands/feet/wherever would be really helpful to her.")
Remember that we are trying to develop our person-centred practice by using all means available. One of the best, cheapest and most rewarding means available is to enlist family. 1) They stop being pains in the neck and start being co-carers/helpers who thereby 2) enable you to do more with less and thereby feel better about yourself and your practice. Most importantly, 3) health and wellbeing is tied up in our connectedness to others. Therefore, the more loved ones help, the better off your patient will be.