Plants vs. Zombies Garden Warfare 2

it is one of Dave's Missions.
Once you collect badges from the other guys (Rose, Kernel Corn and the cool Orange dude) you go back to Davebot and he will have 6 more missions for you.
(You can't miss it)
You will be sent to bait a pirate boss (went so fast for me, i forgot his name, will update)
You fight some zombies. Easy. And you have your 3 AI friends you choose.

According to TheGearGuardian if you summon less AI companions, the Boss is a lot easier and the smaller zombies are not as many as well.

Then the boss comes out. He is a bit tough, but doable.
The only problem is, in the middle of the fight, he throws a curse at you and you have to leave him for a bit, go search and vanquish a zombie with a drum on him. You can easily find him by scanning the area and looking for a red bar on the head (much like the one the pirate boss you are fighting has. You need to find him and kill him within a set time (1 minute 20 seconds i think). Find him fast and try to ignore the other weak zombies. When done, the curse dissipates and you can continue hitting the big boss. This happened to me 3 times during the fight. If you fail, you all die. You can self-revive, but your 3 AI friends will remain dead.
What i did was, self-resurrect, then i tried to res all my pals. Can be difficult because the small zombies seem to all concentrate on you. You might just ignore them and try to kill the big boss, but its a bit harder on your own.
The achievement pops when you kill the main boss (Pirate)