The roof leaks and and needs to be completely gutted.  

Another aspect is here health and likelihood of ending up in a nursing home, that sale can come back in her determination of assets to qualify for benefits.

The following is a partial list of things that wear out or become outdated over time and eventually need to be replaced for every property:-Roof-Siding-Hot water tank-Furnace-A/C system-Electrical system-Plumbing system (inside)-Sewer service line-Water service line-Any concrete exposed to the elements (sidewalks/porches)-WindowsIf you calculate the cost of replacing each of those items and divide them by the expected useful life, then sum that up, you'll come up with a monthly amount that you can expect to spend on capex over the long term.

I drove past a condemned house, the roof is collapsing.

But to me it isn't obvious whether the existing appliances can be depreciated on my taxes since they weren't explicitly purchased (i.e. they weren't itemized on the purchase contract) by me when purchasing the bldg but they were included when I took ownership.And if the answer is yes the existing appliances can be depreciated then does that also apply to other non-appliance items such as the bldg roof or the 3 furnaces in the basement that are used by the first floor storefronts?

I got the house for 20k under market value and it probably only needs 8k roof paint and carpet, What do you guys think, how bad is this deal???

It's probably the hardest path in REI, because you have to understand every aspect of a deal...acquisition, rehab, and all the various exit strategies.

The roof needed some minor repairs where the plywood separated from each other.

BiggerPockets has been such a pivotal tool for me in learning so many aspects of REI in such a short time.I am new to REI and looking to start in the suburbs of Detroit. 

Very profitable and you control EVERY aspect of the deal.