Not being a lawyer, and only for the sake of internet banter, and being only familiar with Illinois practices, I disagree with you, Marian.  We don't know the circumstances behind the wife's agreement to take on the mortgage payments.  There could be any number of reasons for this, one being that she would agree to anything to be rid of the ex.  Did the husband take cash out, leaving a higher principal balance that benefited him and not her?  The court may know, but we don't. 

 I find it surprising that a court in any state would rule as this court did.   The best case I would expect for the bank, is that they might be left with 50% security interest.  At worst, since the sole mortgagor conveyed his interest in the property, maybe a completely unenforceable lien.  Lenders are expected to perform their due diligence.  It doesn't appear to have been done in this case.