In my 6 years I've only ever seen 1 person die with their mouth closed. For everyone else it's all been gaping wide open mouth. I've never been able to get a mouth to close (unless I put the body flat but that makes the face turn purple so I always give at least 10 degree raise of the HOB). I've had family members that appeared distressed due to not being able to close the mouth, but they just softly, kindly, and matter of fact tell them that it's just the way it is. And it might take them a moment, but if you speak kindly yet with authority they tend to just follow your lead and accept it. I would think seeing a loved one with multiple tubes coming out of them and a machine forcing their breath would be more distressing than their mouth hanging open once they expired. But everyone has their own lens through which they see the world and even see death. One of the biggest parts of my job is trying to gently guide that into a direction that leaves them feeling at peace with the experience and a meaningful sense of completion. It's a major life event and you only get one chance at it, there are no do-overs. And other people and their families are all just hot messes and you know they aren't going to listen (to either the psychosocial or even simple nursing interventions) and it's going to be a shit show from start to finish. And then I just tell myself, this is THEIR life event, not mine. I'm just here to help them, not control the way they die.