I am willing to put up the cash to help him preserve my father's share of the house but I'm worried about losing my money.Hoping to urgently get opinions on the situation and for some recommendations of good foreclosure/probate lawyers in NJ. 

Preservation of history through a living museum is my big why.

Given the historic preserve nature, I can foresee rehabbing these older homes with a ton of red tape associated with it.

One of these is that the majority of Dane County towns are "agriculture preservation" with limited density units (1 new lot for every 35 acres is pretty standard in most). 

But typically, the risk of a well planned BRRRR is still only ending up with 5-10% left in it, either for appraisal/rehab cost reasons or preserving cash-flow. 

Simply state that the owner is away, and that you are preserving and renting the property until such unknown or unspecified time as the owner returns. 

For tax properties in Alabama, what preservation improvements generally create the most VALUE add and are usually justifiable?

You may be trying to preserve capital in a lower risk investment and then it may be something for you to consider. 

Thanks for the feedback, I should have added above that the goal is to acquire a small portfolio of small multi-family properties over the next few years to build/preserve her wealth as well as generate cashflow to cover/offset her living expense.

So, our goal was to have it break even, as we are looking more for wealth preservation than cash flow (as noted in some of the conversations above).