There's nothing to find. I don't know how much of Frank Sheeran's story is real or bullshit, but I would imagine Hoffa was killed and disposed of much like he was in "The Irishman". Thinking they put Hoffa's body in a drum and buried it somewhere when they could have destroyed it in some mob owned crematorium is ridiculous. If anyone knows what actually happened to Hoffa it died with them. His body or traces of his body aren't ever going to be found. Anyone making a move against someone like Franzese is committing career suicide, literally. Like AC said, Henry was living in the open and he was an actual rat who testified in court and put people in prison. The mob was a lot more powerful back then and I'm sure if they wanted to they could have tracked Henry down in the 80's and killed him.