Went ahead and picked up the letter at the post office. All it was was his list of "demands", which he had already cut and pasted into an email.
He had the list notarized, spelling mistakes, rambling and all. Says I have until May 22nd until a law "suite" is filed in the county he resides in.
My gut feeling is that he does not have an attorney that has agreed to work with him on this. Otherwise, I would have figured he would have worked with the attorney and had them send the letter.
I've talked to an attorney who, like previous posters have said, doesn't believe my father has much grounds for a lawsuit. She said if he put me on the deed with the intention of passing on the home to me, that that would be construed as a gift. And since I have never lived in the home and it is his primary residence, property taxes, HOA fees and insurance would be his reponsibility. The gift and no former expectation of spliting costs associated with the property would be enough that she didn't think any respectible lawyer would even take the case.
That said, my wife is very upset about the entire situation and wants to see if we can formally hire an attorney to respond to the demands and cite the reasons why my father does not have a case. She wants to try to preempt a lawsuit and having to have to pay our attorney for travel expenses, etc., in addition to the actual work. I don't know if something like that would work to have a civil lawsuit thrown out before it is even considered. Could it?