Once you have returned both spirits to the church, a series of shocking things will happen that ends with Madeline taking over Rosa's body. And regardless of what Madeline says, there is something Joey can do about it.
Hint 2
What has Joey got to work with? Madeline's totem doesn't work here, and Joey's ghost breath does nothing to either Madeline or Rosa.
Hint 3
The only thing he's got is his tie. If you right-click on that tie, Joey tells you that it's the only part of him that Rosa can touch. That means he can use it to touch Rosa too -- remember how he used it on Rosa at the end of Blackwell Deception?
Hint 4
When you're out in front of the church (and after you've grilled Madeline on every possible subject), use the tie on the pair of them.
