I would tell him if the item is valuable then he needs to call the police and report a theft and to give them your contact info if he'd like you to verify you brought it in at his request and what condition it was in -- open, torn, or sealed and in decent shape.   

What improvements will seal the deal quicker?

Of course, a new foundation with the proper drainage tiles and pumps all sealed tight would be great but not on your budget.

The surround in my kids bathroom has this surround, with the side pieces (like L's) overlapping the rear peace a little, glued in, and sealed with caulk...not a drip in 15 years.  

Mobile /manufactured homes depreciate very quickly so you'll need a full inventory of each home, sqft, year, TX seal or HUD label #s so you can see if there are any liens or other encumbrances on the properties and homes.  

@Timothy Riley - The 2 sump pumps definitely had us scratching our heads in there, but made it work and sealed the 3rd additional catch basin. lol I'm glad that you were still able to find success when the market turned.

They pulled a vacuum on the front door and caulked windows, put little foam inserts behind receptacle/light switch plates, installed new door seals, re-mastic'd the ducts and blew in new insulation in the attic for ~$300 I believe. 

^^ That is correct Donald.For me , i was dealing with cast iron, but had (as a back up plan) figured out a way to use a combination of the pvc offset flange with the mating seal for flange that would mate to cast iron.

There was surface mold in the attic only above the pool which was remediated and sealed in 2013 with a 10 year warranty - when we the owners purchased it and lived there. 3.

Looks like a good idea but I doubt my tenants would notice as the washer was leaking from not cleaning the seal and they didn't notice that...