how to secure sheetrock

As I worked on the walls and discovered loose tile - I find that this corner of sheetrock is moving. It's not really connected at the bottom nor at right. Not that it moves a lot but enough to where I'm concerned about securing the sheetrock up to the tile. You can see in the lower corner where the tile curves in from a poor repair years ago. This is on the plumbing wall, it's about 8 inches between sheetrock on both sides.

I put a clothes hanger wire in the hole but didn't find any stud to either side - I could only get wire in about 4 or 6 inches to the sides. When I checked to the right it sounded like it tapped on bare tile.

Any suggestions for how to secure this corner of the sheetrock?

I greatly appreciate help. I'm waiting to get these repairs completed so I can have my one bathroom back!

Sincerely,
bamakodaker

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