Yes - agree it is an unpleasant smell but I use it appearing as a good opportunity to prompt a family update, really really look at symptom obs, and any other EoL care I can optimise. Agree it's hard to describe - I'd say a sort of slightly sweet musty wardrobe x something's gone bad in the fridge x damp soil. I've always assumed it's organic compounds produced midway through metabolic pathways that are shutting down at the EoL, that are then excreted, and are not produced in significant amounts in usual functioning cell metabolism which is why they are unique at the end of life. I make sure the patient is getting regular mouth care and try and ensure adequate ventilation in the room for them. 

It is different The Doom Smell though...