Here's one for all you tile experts.
The soap dish/grab bar has fallen off the tiled wall in the kids' bath. Of course it was coming loose for some time before anyone thought to mention it so some moisture got behind it. Apparently the tile job was done on regular green-paper bathroom drywall; the ceramic dish coming out took the paper, the thinset used to glue it in, and some of the gypsum with it, what's left is a hole in the tile with uneven, slightly damp gypsum behind it. The tile is otherwise in good shape.
I've got a hair dryer set up to try to dry things out, but I'm wondering what to do next, short of tearing down the wall and starting over with wonderboard. If I just goop some thinset on there and glue it (or a new one) back in I don't expect it to last long. But I can't think of too many other options, unless there is a dish that can be held in place mechanically (ie. screws) and sealed.
Any advice appreciated.