Okay...
PC has Mummy Rot and is screwed (no cleric, no cure disease, no remove curse, miles from anywhere)... A player has suggested to kill the afflicted PC and then just Raise him later. So...
1) Once dead does the disease halt or does it continue to its grisly conclusion?
2) Once Raised does the PC still require curing?
My gut feeling says no & yes...
Mummy Rot is at the same time a disease and a curse.
Once dead, the disease can not continue to do its effects.
But once raised, the curse has not bee removed, so the curing is still necessary.
Are you certain about that? Because, as far as I know, a corpse is a mere object and the mummy rot curse can't affect objects; they've no constitution or charisma to loose. Seems to me that the mummy's curse will cease to affect a creature as soon as it stops being a creature.
The corpse cannot lose Con or Cha; however, the raised PC does have Con and Cha. The curse was not lifted; it is simply in abeyance until the corpse is reanimated in some way.
I'd rule the corpse rots away and suffers the same effects if the victim kills themselves early.
The character that made the suggestion is being a bit metagame-y, but RAW isn't on their side. Even though the ability says "dies from mummy rot" the actual disease doesn't inflict damage. In effect what is really happening is, "character dies while under the effects of mummy rot." So if the character were to be killed off without removing the curse first, they would still suffer the result of being turned to dust and unable be raised without a resurrection or more powerful spell/magic (as Frankthedm mentioned).
After that as raise dead states it does not remove magical curses or diseases (and res and true res refer back to raise dead), it is still in effect and needs to be cured after being brought back to life.
It is an interesting question, and they are in a dire situation. They do want to go gamey to get away from the effects. Some thoughts...
1) Amputation of limb. If face, neck or chest, ah well.
2) In the wilderness? Well start looking for druids, fey, mountain temples.
I too am thinking the curse is still on the body, and could be transmitted if the players aren't careful, but they might not get the chance. My reasoning follows Frankthedm who has a point. They are cursed with a con draining disease, when they reach 0 con they are dust. Killing someone removes all their con. Their life and health are gone. If they were killed without the curse, they would be whole, if they are reduced to 0 con while under a curse that means dust when 0 con... well the corpse ain't going to be pretty. I'd say it mostly dusts away, with a bit of a shell left (it didn't get into the whole of the body and take all the con with the disease). So something left for powerful raising magics, not enough for ye standard raise dead.
In this type of situation, it is time to think smart, be impressive and trust in the DM, not meta-game.