Would you say the neighborhood is gentrifying, stable or deteriorating? 

Carpets have a finite life and will deteriorate no matter who lives there.

The brick chimney was so deteriorated that it virtually imploded with hardly a tap of a hammer.

With that said, the deterioration of the unit(s) may occur much quicker. 

Can the obsolescence or physical deterioration be reasonably cured?

Long story semi-short: the other daughters granted, lets call her "Paris" which is a daughter of his, they granted her full permission to own the house but she was never officially put on the deed it was a verbal agreement saying "yea Paris you can take control of the property" So eventually after sitting for so long  the house was deteriorated and was agreed to be demolished by Gary (who is Paris's nephew) for 28k around 2008.

You'll also want to ensure you have a good property manager to look after the upkeep of the property if you are not there to notice anything deteriorating or which may need attention.This article goes into a lot of the considerations about whether to form an LLC or not: https://www.mmpph.com/wp-content/uploads/2019/04/May-2019-newsletter.pdfThese are all things you will want to discuss with your attorney and CPA.

The State Department of Transportation I am assuming this must want to widen this highway and that way these are in this deteriorating mode.

Personally I know things break and tenants use/destroy everything, homes deteriorate over time, so having money set aside for the roof, boiler, water heater, etc., might be a good idea.And remember, these are just numbers on a spreadsheet.

It could lead to an overall deterioration of complexes and the city.The other parts is a tenants rights part.