wholesale decorative ceramic picture tiles

(sob story) my dad was a refinisher and generally knowledgeable guy who flipped homes when I was growing up, he got cancer while I was closing on the house and never got to come out and see it, passed a few months later. Thanks for your time and sorry for the long winder I've attached some pics below, can upload more as necessary. If anyone can recommend a solid course of action that would be a blessing, or knows of a professional in socal who I can pay to inspect and recommend (or maybe perform) a course of action, it would be greatly appreciated. I would prefer to do the most minimal viable course to get it functional presently and not to remodel as there are many other fish in the fryer so to speak. 4'x4' Custom Photo Ceramic Tile with Easel Back actual size 4.25x4.25 tile (7.8k) Sale Price 9.00 9.00 12.00 Original Price 12.00. I haven't done anything yet, the bathroom floor has the same stone tile as the shower walls. I'm wondering if that combined with proper sealing is a viable option at this point or whether the horse has left the barn and it needs full replacement. I bought some 2 part epoxy from lamlock for stone patching, and thought I might re grout and re silicone the parts that need it just to keep it functional. Tesoro offers a wide range of Porcelain & Ceramic tile, Natural Stone, Luxury Engineered Planks & Tile, and Decorative Glass products including Pool. I didn't realize stone sealer was a thing until well after the occurrence of these holes and the stone degeneration. My main issue is I'm not sure what kind of stone it is and whether it is salvageable at this point. I do most things diy and would prefer to do so, though I'm not opposed to paying for help as in my experience diy tends to mean more time and more money (I enjoy learning and the experience generally speaking). I've stopped using the shower as I'm worried about water leakage, but am a bit overwhelmed due to my inexperience.

The grout is also cracking or has cracked away entirely in some places along the edges where the stone tile meets the shower floor tile. I tried to keep the shower squeegeed as often as I'd use it but there were some late nights I used it where it probably didn't dry as much as needed. I'm a bit of a young idiot without much help from experience (in case you are wondering how this facepalm worthy behavior happened). The shower started to have the stone tiles discolor and crumble. I bought a house a couple years ago and unfortunately didn't get any information on maintenance or upkeep from the seller as it was sold by someone in another country, who might've had some animosity over having to sell due to circumstances of their own.

Tldr stone tiles are crumbling and discoloring in my shower and the grout has disappeared in some places, looking for recs on if it is salvageable or needs to be redone wholesale.

Wholesale decorative ceramic picture tiles