Over time the casing tends to disintegrate and wires touch, causing the electric to a, cease to work and or catch fire.

Old houses have cast iron pipers that will disintegrate (because of age and/or foundation shift).

They'll disintegrate in about 15 years.

Most cabinets are destroyed by water being absorbed by the presswood and the glue disintegrating and/or the sawdust/chips swelling.

Their investor base would disintegrate pretty rapidly. 

(It’s actually 2 houses) in the leech field, he called it something else no longer leech field, they’ve got a more modern name, one of my diverter valves had become crushed as the distribution box had disintegrated on top of it causing 1/2 of the field to be overworked making it now inoperable leaving maybe 15 years left on system whereas if it had been maintained there would be 25 years left.

It matters if the asbestos has been disturbed (or is disintegrating), how accessible it is and if it needs to be removed or not. 

Not even during the rainy summers.The only explanation I can think of, is this thick mat of disintegrated leaves and debris had been acting as the top layer of the roofing membrane, and once we cleaned it all off, the old roof below started to leak. 

If you are talking about the bottom of either of the sides, those are usually a single cut piece of MDF/OSB/Presswood, and once those have disintegrated from water it would be difficult to splice a replacement piece in at just the damaged area - but you could disassemble the cabinet, use the side panel as a template to cut a new panel from plywood, put it back together and paint it.

@Ulrich FairclothYour "partner" is in a disintegrating marriage (another partnership); already has bad credit (which is not likely to get better in the near term if he is headed for divorce); your talking about "bidding" on a duplex as your first investment, with your partner occupying half (making your investment returns poor, unless he plans to pay market rent).Personally, I'd steer clear of a partnership with this individual until he has his life in order.