Don't seem to use their ranged weapon for some reason, they unequip it and go fighting with their firsts.
Sounds like they don't have any ammo, or the DEX is lower than the STR making melee the most effective weapon in the AI calculations Yo.
In my experience, they start punching face as soon as something gets close, the same as Brood Keeper summons do. Until then they use thier shortbows. Just use the Command Companion tool or "follow me" command to keep them at the back.