While it is true that:
"The spirits of the just are exalted to a greater and more glorious work; hence they are blessed in their departure to the world of spirits. Enveloped in flaming fire, they are not far from us, and know and understand our thoughts, feelings, and motions, and are often pained therewith." (TPJS page 325)
there is a limit to the depth to which they understand our thoughts, feelings and motions except God reveal it to them (which may be the very means by which they understand them at all), for we also read
D&C 6:16 Yea, I tell thee, that thou mayest know that there is none else save God that knowest thy thoughts and the intents of thy heart.