Did Leo end up ultimately testifying and letting Frank know that Willie Killed the guard?

Hopefully you've seen the movie so its not a spoiler (I don't know how on this site you cover words until people highlight or click on them) but Leo's character ultimately reveals the truth about Frank's business. He does get a pass for the beating of the officer (but clearly the officer gets paid off), but the movie doesn't show that he "snitched" on his former friend Willie.

So did he testify against him? He was probably already facing life but still if he's honest about Frank's business then clearly he's got to be honest about something much more significant.

This movie needs some discussion