A lot of people have asked about the facial expressions of the deceased.
As a very junior doctor in adult medicine, I wrote a lot of death certificates. Unless I happened to have already confirmed the death myself, it is necessary to go to the hospital mortuary to view the deceased, confirm in your own mind that they are the same person you knew on the ward and to check for devices such as pacemaker (as in physically run your hand over their chest to ensure there isn't one as you will be liable if you explode the crematorium).
I saw many patients after death, having known their facial expressions when they were alive, having know the manner in which they died. They usually looked quite different (although obviously reminiscent) of when they were alive, even if very recently deceased. It is commonplace for a deceased person's face to look "hollowed out". Sometimes the mouth is very wide open or gaping. The eyes don't always remain closed. Sometimes they may look as though they are grimacing, or frightened. It doesn't mean that they were feeling this way when they died. People's faces change in the minutes, hours, days or weeks after their death. There is no voluntary control of muscle (for obvious reasons) which can be such a big part of what makes up the character of someone's face. Muscles can become slack, or shrink/contract resulting in a grimace, or a bit of both. If you have seen your loved one's face after death and were disturbed, please rest assured that whatever facial expression they did or did not have, did not reflect their last moments.
Also, some bodies decompose more rapidly than others, even when moved quickly to the hospital mortuary (where they are chilled immediately). There may be very little a funeral director can do about this. I have seen bodies the very next day having been cooled overnight showing signs of decomposition. Sometimes it is related to the mechanism of death (eg any type of bowel perforation or sepsis) and sometimes I couldn't say a specific reason. It could be affected by something as simple as when the last meal was taken maybe? This was sometimes upsetting for me as a doctor having just known a person on the wards, let alone as a friend or relative. It does not feel nice for someone's body to change in that way but it is an inevitable part of death. I suppose the comfort is to remember it doesn't affect the person who has died.