This is complicated and based on a number of factors. Did your father have a Trust? If not, did he have a Will prepared before his death? Could this 'letter' be construed as a holographic Will which would need to be in his handwriting and signed? Whose name is currently on the deed--your name, your dad's name or your dad and his wife's name? From your statement and question, it doesn't sound like your dad's wife's name was on the deed at all.
If the house is in your dad's name only and he had a Trust, then the property is distributed as per the Trust. However, if there is no Trust, and the name on the deed is only your dad's name, the property would need to go through Probate. A lawyer would need to determine if the 'letter' is binding.
Answered on Nov 02nd, 2014 at 3:08 PM