When he vacated the property and returned to his home state, he left under hostile circumstances and left significant damage at the house.

The areas probed still seemed solid, but be aware that some types of wood destroying fungal damage will only be detectable once the wood has properly dried out.

I email or text them once again to let them know in writing when I will be filing a forcible entry and detainer (eviction) action and let them know that time is short but they can still avoid the consequences of a damaging eviction filing.

. - Evidence of water damage in the basement. 

A tenant can do $20k of damage pretty quickly and skip town never to be found again, if you aren't careful.  

They did not make an offer to pay rent/damages/legal fees before the deadline of the eviction. 

I’m worried they won’t leave or damage the property.

But that means we have to push this out even further and the longer the issue isn't addressed, the more damage that is being done.

If you buy the next deal correctly you won't damage the inherited property or kill the current cash-flow.

I would get a professional opinion from a qualified contractor , you may have storm damage already that could possibly be covered by your insurance