You know, there are a LOT of factors that come into play when someone pases away that will determine how long it will take for them to decompose. I know this isn't the kind of answer you would have hoped for, but there are a lot of scientific factors to take into consideration... The morgue may not have allowed you to see your mother in law because she may have died and not been found for a day or two, which would expedite the beginning stages of decomposition. Decomposition startes IMMEDIATELY following death, and then the other stages become present. The first being the mortises: Rigor (stiffness), algor mortis, and pallor mortis, which is more or less a color loss...The blood sinks to the lowest tissues of the body, mostly collecting in the thighs/buttocks where the person was lying when they passed...Theoretically, depending on cause of death, temperature, presence of insects or carrion feeders, length of time exposed to elements, etc a body can last anywhere from a few days to a few years in an unembalmed setting... There was probably some discoloration and odor that the morgue staff did not want to expose you to. The funeral home staff will be able to take care of this, as the body is kept in refrigeration in the interim before embalming, and they have very gifted staff that cosmetize the deceased and make sure they look as they did in life... When they are embalmed, the body will hold for quite some time...There have been instances where bodies have held over hundreds of years. The mummies of Ancient Egypt come to mind in this topic, but that is a different process.... I hope this helps, and I am sorry for your loss.