Without him mummy would soon go to pieces (8)
I believe the answer is:
embalmer
'without him mummy would soon go to pieces' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'without him' is the wordplay.
I cannot really understand how this works, but
'him' could be 'em' and 'em' is found in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for embalmer that I've seen before include "One should preserve" , "Mummy creator" , "Who made mummy" , "Mortician who treats corpses with preservatives" , "One preserving bodies" .)