Both times the toilet supply line snapped (don’t use the overlapping metal type that look like knight’s armor or snake skin) both claims were over $30k.

Wholesalers who respond on this forum have to have the “thinnest” skin imaginable.  

I have a lot more skin in the game on this one for sure..    

No one has more "skin in the game" than a PMC as they have to deal with the property every day until an owner sells or fires them.Also recommend finding your own Inspector and not one referred by an agent.

Did you see any studs or bolt patterns sticking up around the small concrete dome on the surface of what it looks like a brick pad? 

No skin in the game might mean a lackadaisical attitude towards it.And you may have maturity issues to deal with--every child is different.I's say a good starting point might be letting him earn a % via sweat equity over time, starting at zero, and reassessing every 3 months as he makes improvements on it (or manages it properly, or whatever).Once a certain % is done that amount moves to him on paper, vs on the deed, if you have issues with him not applying himself to it (or being a PITA to you about it), I'd say sell it and let him move back home until he is more likely to handle it. 

The only way I see this working out is to put such as a Raceway non-metallic PVC surface mounted on the wall, from the light switch, up the wall to the ceiling, along the ceiling to a position of choice.

Will you remove/scrap all of the old failing caulk and surface, clean the surface properly, buy and use a decent/superior caulk for the location, apply it when the weather conditions are appropriate, and perhaps paint/seal if the location and materials call for it? 

If I'm the seller and I know there are quite a bit of issues now surfaced, I have to inform the next buyer.

You can't do business in a state like that, particularly Real Estate where the game is rigged in favor of the tenant...who has zero 'skin in the game'.