After you make Lisa realize that she's dead, go into the living room to discover something has happened to Rosa.
Hint 2
To be more specific, Gavin has happened to her. She grabs Joey's tie, pulls him into the void between the worlds, and says goodbye, leaving him floating in nothing. She was clearly brainwashed, but that doesn't really help much; we're still here. Now what?
Hint 3
After a moment, Joey seems to see something we can't. Float the way he's looking, to the right, to find --
Hint 4
-- well, not a friend, but someone we know, anyway. Talk to Madeline to get her take on things.
Hint 5
Madeline says the link between Joey and Rosa is being dissolved. When pressed, she says the link is what enables Rosa to pull spirits into this void. And what does Joey use for that?
Hint 6
It's his tie, remember?
Hint 7
So use Joey's tie on Madeline, and after a ladylike snort, she'll bring the two of you back to the real world.