It's only to relieve a creature of suffering. There is not lasting benefit
it offers no recovery, but may ease their passage.
I suppose there is a case to be made that a numb creature is immune to being nauseated, but I would check with your DM.

I don't know if such a punishment should be leveled against an invocation player. sure it is usable at will, but you still need the 10kgp Material component and all the other restrictions of the spell apply. Making someone loose xp and take cha damage just seems too steep a price for at will, afterall, Clerics can cast it will no ill effects all they like.
I think you misunderstood, the invocation I proposed had no material component. The price was Cha damage and XP reflecting strain on your soul (cha damage) and a price paid to whatever otherworldly force controls death in your setting (xp). I apologize for not being clearer.

Candle in the Void
Greater; 7th
You channel raw Eldridge energy as a beacon to lost souls, enabling you to use resurrection as the spell. On top of needing the required material component it also does 1d4 con damage as a result of physically channeling that much raw energy which goes away after you have rested for eight hours.
This works too, I had no problem with your first resurrection invocation balance wise, but thought the idea of sending the warlock's soul out to buy back the soul of the fallen creature was neat enough to merit putting it out there.

Every high level opponent with Invocations anyway,it's No worst then some of the tricks Wizards can pull with it. But I like your fleshing out of it. However Doing so seals your usage of said invocation as its energies are focused elsewhere. seems a bit off, if one can cast invocations at will all day, why would an item which has an invocation in reserve not allow you to cast it? Still again, to balance if it needs a downside...
Couldn't a high level opponent buy a 1up doll?
If the invocation's eldritch energies are bound in a loop from the doll to warlock, then it prevents the possibility of warlocks selling these dolls like hot-cakes as they cannot create X copies, only the one.
That being said, the material component may make this possibility null as wealth levels vary wildly from game to game.

If your DM is ok with that possibility, then by all means. I just tend to err on the side of caution as my DM tends to be uncomfortable with homebrew and therefore more permissive of more restrictive spells/invocations. The potential for abuse is always there in his eyes.

Other than that, I'd only suggest shifting the shaken condition from the Doll invocation to the resurrection invocation, representing minor system shock from being pulled back from the brink.
Channeling an invocation like Curse of Despair through the Doll and adding the shaken condition on top of that could be too powerful, butchering saves like no-body's business (-2 from shaken, -4 from Curse of Despair, your caster friends would be jumping for joy, but your DM might cry ;-) ).