It will all boil down to the quality of the narrative you give it - regardless of the actual die rolls.
I would recommend that you have a thought out plan for what the PCs will do if the favored NPC dies.
Can he be brought back? Resurrected? Healed in same manner? Act of the gods?
This type of scenario almost always lead to some epic quest the PCs will have to undertake (for honor of their brother).
I would recommend that you have a thought out plan for what the PCs will do if the favored NPC dies.
Can he be brought back? Resurrected? Healed in same manner? Act of the gods?
This type of scenario almost always lead to some epic quest the PCs will have to undertake (for honor of their brother).