So I read all the previous posts. But here is my confusion. So the grout at the tubline is cracked in certain areas. Which is allowing water to go through and drip to the lower level where it now has a destroyed the kitchen ceiling.

So should the grout at the tub line be completely removed and re grouted? Or should the grout be completely removed and silicone caulk just be used to seal the tubline?

Grout should not have been used at the tub / tile line. It is too hard and when someone gets in the tub it moves and cracks. Remove the grout, use masking or painters tape to get a nice even line, caulk with silicone, let sit for a couple of minutes and remove the tape. You will have a very nice looking flexible line.

Brian nailed it. You can get colored caulking to match grout.

Chuck

When we install our fixtures we use Dap White Tub and Tile Caulk. Great explanation from Brain. Good luck, Tom