This is typically done with oxygen bleach and sealing the wood.

Something I have noticed here in Corpus is that many roofs have ugly stains that can be treated with a bleach solution for almost no cost comparatively.

What I ended up doing was taking buckets of bleach water and "mopping" the walls and ceilings.Change the water frequently and go a bit heavy on the bleach.

We first sprayed ~50/50 bleach everywhere to just kill gross bacteria and then went back with odaband (fungicide).  

Tile is among the least inhospitable surfaces to multiple drug-resistant organisms/superbugs, and if you work in a hospital or a nursing home, you've seen people die of superbug secondary infections, and you don't want to bring them home to your kids.Medical professionals also tend to put a lot of faith in chlorine bleach.

We're talking about tearing up all the pee-soaked carpet (dogs..) and bleaching/disinfecting the concrete foundation underneath, replacing a majority of the second floor sub-floor, fixing the roof, fixing the HVAC, repairing the garage (door hanging on by a thread), scrubbing and disinfecting all the cabinets (roach feces everywhere), tearing up and replacing the landscaping, fixing the roof, inspecting and repairing any water damage... the list goes on and on.

Sure if they have renters insurance they should file a claim, and you can see if you get lucky and they cover the entire cost  also keep in mind that you’ll probably have mold, so that needs to be remidiated by bleach or something else before new boards are installed  Otherwise, since they are a decent tenant, I’d try to negotiate and work out a compromise with them.

Bleach kills mold.

At the same time we cleaned down everything with bleach and other cleaners like TSP.

Bleach or no bleach?