Ok I found out not to long ago but some ppl don't know that u use emotes to help kill him. Here's how u do it:
There are 4 platforms in each a corner of the bosses room. When the boss says "it's time to act!" everyone run to a platform( try to each go to a different one) and stand on it. As u will notice there will b a animated picture on the screen of the platform ur on. Those animated pictures correspond with 4 emotes (wave, LOL, dance, and no way!). So while ur all on ur plat forms do the emote that corresponds with the animated picture on ur platforms screen. When all 4 platforms r successfully charged the director droid will b damaged a lil, his shield will drop, and he will b stunned.

If u have a good team and r organized well this should go smooth and u should kill the boss in no time!

Hope I helped good luck everyone!