We have areas of tile that have actually fallen off near the bottom of the shower tile(right before where the tub begins,underneath the faucet). This is in an upstairs bath and you can actually see empty black space where the tiles are missing. Also, all around the rest of the tub edge, the tiles are beginning to weaken. I am seeking HELP, as my spouse can't seem to fit this into his HONEY,DO...list of things to do. Please give easy to understand advice, as I generally don't do repair jobs.