Quic question, can Farkas, Vilkas, or Aela die when they are followers after the end of the companions questline?

I believe so. I accidently took a two handed sword against Aela's face killed her. Had to reload from a previous save. Couldn't leave her body there in that crypt.

Totally. Once all of the missions that involve them are complete, (The Companions questline) you can have them follow you, and just like any other follower, they can be killed.

ya i know for a fact farkas can die, i've seen him die before

Its this reason that I do not have a follower as I do not want to watch over them so they do not die. Farkas, Vilkas, & Aela are my favorite ncpa in the game.

Yes they can die if you hit them when they crawling at the ground with an arrow to the ..... chest. Try download UFO so you can set them essentials.

It's pretty difficult to kill them, and it's usually the PCs fault if they do die. Regularly Wabberjack your follower and they should be able to handle anything you can. Choosing a complimentary follower who never gets between your attack and the enemy really helps their survivability. I really love having a mage follower, because at the first sign of trouble he runs to cover and throws lightning at range. The Companions are all melee fighters, so I guess it would be more difficult to avoid hitting them.