Death Grip (2012)

In an effort to set his life straight, Kenny Zemacus checks his autistic brother Mark out of the care home where he's spent the past fifteen years since their mother's death. When Kenny reluctantly brings Mark on a last minute museum catering gig, Mark unwittingly entangles them in a dangerous heist involving the museum's showpiece -- the Silver Coin of Judas -- and a murderous satanic cult known as The Knights of Judas. The two brothers are propelled into the cult's demonic world where they must fight for their lives and face the depths of their own dark past.

Unfortunately the movie Death Grip is not yet available on HBO Max.