Companions will make use of Stimpak's to heal themselves but they will not deal with their own crippled limbs (on hardcore mode anyway.) How difficult would it be to get Companions to use doctor's bags, if they have them in their inventory, to heal their own crippled limbs?
If such a thing isn't too difficult I could try to set it up myself. I don't have much experience in writing mods myself though. If someone else thinks they could write a mod to do this it would be appreciated. :)