Doing a subject-to where person on mortgage is deceased

[Nathan Habben]

I looked at a house today I was thinking may be a good "subject to" candidate. Then I found out the owner had died and it was his mother that was showing me the house. She told me the mortgage is still in his name and she is paying it and would really like to get rid of the house. I knew I had a motivated seller so I got more info. Before I make an offer I'd like to know if anyone forsees any problems having a deceased on the mortgage? Shouldn't it have gone to his estate, then have been given to a relative, or at least a trust when he died? In other words, is this an unusual situation?