Cannot beat Namir due to dodgy AI in Director's Cut
Solution 1:
The bots should definitely be capable of killing Namir fairly easily (as he never targets them or attempts to destroy them), anecdotally I can state that this is how I defeated him myself in my first run of the Director's Cut, right down to the use of the AUD to hack the computer.
Are you definitely sure you hit 'Target enemies' and not one of 'Disable'/'Enable'? I can imagine a fair bit of muscle memory being at play if you're doing some sort of pacifist or no-alarms run as making the bots hostile to enemies runs contrary to both of these.
My advice would be to reattempt the fight the same way; at least now you know the location and can easily throw down an AUD to start up the bots again without too much fuss! It's possible some quirk of the AI had the bots fail to target him properly, he does still move around a lot which could cause some confusion. "Have you tried turning [the game] off and on again?"
If all else fails: you have all you need to kill Namir in the statues around the room(s). Every boss fight gives you ample supplies to account for the possibility that you're lacking in initial resources. Stunning him with any sort of grenade or mine will give you the opportunity to raid the nearest container before he opens fire. There should be a plasma rifle, combat rifle and/or revolver along with ammo and more grenades.
General combat strategy would be to hog corners (his plasma rifle kills you very quickly if you're in the open), stay alert to his movements and shoot him as he's jumping over walls since he is incapable of returning fire at this point. Be wary of the grenades he'll drop every now and then; he won't shoot for a few seconds after doing this move so you're free to turn and run, just be sure you're back in cover.