A unit is always considered to be in range of its own Aura abilities. Even amongst 9th edition codices you have to check to be sure. As long as the keywords line up, the Aura will affect the Character in question.
Drazhar wrote:Master of Blades (Aura): While a friendly INCUBI unit is within 6" of this model, each time a model in that unit makes a melee attack, add 1 to that attackās wound roll.
As Drazhar has the INCUBI keyword, he will benefit from Master of Blades.
Typhus wrote:Lord of the Death Guard (Aura): While a friendly DEATH GUARD CORE unit is within 6" of this model, each time a model in that unit makes an attack, re-roll a hit roll of 1.
Typhus does not have the CORE keyword, and will thus gain no benefit from this Aura.