The game Suicide Squad: Kill The Justice League is supposed to be a sequel to Arkham Knight, meaning Batman is supposedly dead in this world. In what way, then, can he assist the Suicide Squad? In the same manner as always.
Despite having destroyed the Batcave, Batman maintains a wealth of files at his fingertips at all times, and there are contingency plans in place to protect that data. I will predict how the game Suicide Squad: Kill The Justice League will go based on the comics and TV iterations. So no real spoilers.
Batman will be in Suicide Squad: Kill The Justice League
Metropolis is facing a dire situation as Brainiac is attacking and there are no superheroes to stop him. A number of the Justice League members are under his control and on his path to destruction. This leads the government to dispatch the Suicide Squad to try and stop them.
In a sense, Batman never fully trusted the Justice League, which is one of the reasons he was kicked out. Batman believes that everyone, even himself, can be corruptible, and he is totally right in this case. In order to prevent disaster, Batman devised emergency plans for each member of the Justice League.
Guess who was right like always? Batman.
In these plans, they are not going to be killed, but knocked out or incapacitated. This plan, however, was used by the Justice League members to kill them during the events of the Animated Series. I feel like Batman has hidden these files just in case.
There should be a system hidden in Metropolis by Batman that goes off whenever the media calls for Justice League members to be stopped. The job will fall to Harley Quinn and the others to locate these points and retrieve Batman's hidden archives to retrieve old messages and tools. In this way, these members can beat Superman and the Justice League.
I see Suicide Squad: Kill The Justice League playing out as I mentioned above. In the context of Suicide Squad: Kill The Justice League, it would make complete sense to refer to Batman again. It's possible I'm wrong, but I doubt they won't look for files Batman has.