can you still get the faith keeper rocket launcher?

[Biggie_]

and how please

[EckyThump]

You need an Episode: Echoes pass, and can then earn Faith Keeper from Episode: Echoes activities and Failsafe's HELM rewards. You can't buy the pass in-game however, the only way to get it is through the Final Shape Annual Pass edition, or Annual Pass Upgrade for players who own Final Shape already.