Mortgage Information -Off Topic

Read an interesting article on mortgages in our local paper. Seems as though the writer sold his house to a buyer, who "assumed mortgage" over 10 years ago. In the interim, house was sold at least twice, w/ the same terms. Present owner defaulted, and the mortgagor is looking to the writer as recourse. Legally, mortgagor has the law on his side. It could have simply been avoided, had the original sale documents contained the words "FULL ASSUMPTION" of the mortgage.