My followers never die, even on master.

I don't see the need for invincible followers.

I've left Kharjo in a pendulum blade trap for an hour without him dying. Try it, then tell me it's false.

They don't die in traps to my knowledge but if you look to my previous post, they can die without you personally delivering the killing blow I believe they can only die in a fight though. I don't know about falling from great heights either...I've seen tonnes of youtube videos like "Fus Roh Dah *insert follower here* but I don't know if they've actually died because I've not sat and watched them all

I've seen Kharjo killed when assaulted by multiple Deathlords, pendulum blade traps knock the follower away, so they can't be hit by them while in the down position.