The type of helicopter was Bell 407.

Iraqi army helicopter shot down by IS militants over Mosul

Probably hit by another FN-6 and those small helicopters hardly stand a chance to survive a close hit.

As I read, the IA-407’s are equipped with MAWS supposedly which also can dispense flares automatically when a missile is detected. The video starts late so we don’t see the actual engagement to see if there were any flares dropped.