The home needs a roof and siding replaced to make it look presentable, the inside has already been inspected and approved for tenancy.I have 16k cash on hand, how would it best suit me to proceed with the financing to benefit cash flow and taxes?

I just had a new roof put on a duplex.  

Odds are in your favor it isn't.Obviously, first repair the plumbing & make sure the roof, windows, doors & foundation are water-tight.

The roof looks like it might need some work, but that could have been an illusion from the pine needles.

It's basically the same as if the roof were leaking 5 years ago and then you replaced the roof.

say you were set on buying a place at 100k and found out about the leaky roof?

Your mgmt should tell you about the roofs or point out and structural, aesthetic, hazards, plumbing, etc issues and seek bids for work.

It has on it - a house with a hole in the roof , and a mobile home(no one knows where the title is.

Based upon what you are saying, I personally think it's a bad idea that will ultimately end in disaster for your son, based upon his medical condition and his inability to earn a legitimate and substantial enough income to cover any deficiencies should a tenant tear the place up or another significant repair is needed such as a new roof or a new heater.

Just got a notice from my insurer to "Inspect and Repair, or Replace Roof" on my 4plex within 30 days.Huh, wha?