There are many posts, even in that very link, that suggest he does drop elder beads. Regardless, I never saw him in the cave after many hours, seems like he should be there but I dont think he is.

I just tested this on my bard.

Used Faction song on Coldain and got to Amiable.
Use Gnomes to drop my faction, each time I would recon. Once It dropped from Amiable to Indifferent, I clicked neck.
It remained Indifferent.

Those faction hits from gnome are 50 I think, the neck is supposed to increase by 100, so it should've bumped me back above Indifferent to Amiable if they stacked.

tl;dr - Doesn't stack with bard song.

But it's still a junk buff!

Doesn't fill a slot, its hidden lol.

Really, has 0 use for a bard :(.

:(

Zander figuring out he can camp elders in 5 minutes and not have to run in circles for $$$$$$$$$$$$$$$$$$$$$$$$$

This suggests that he does not drop them. That while they are in the area farming the Eldar's they would kill him if he showed up.

Show me the many other posts though. If you want to get something changed you need to come with links and quotes. Nilbog isn't going to make stuff easier for us unless we can prove it was so. Don't get me wrong, I would love to see him drop the beads.

Edit - in addition to the above from this link:

second to bottom post. Not to mention they are called ELDER beads.