(married couple sold rental real estate to son for $28,000 in return for promissory note in wife's name; note could not be sold or assigned; husband entered nursing home and made Medicaid application; state Medicaid agency determined that note was available resource and, as a result, husband ineligible for Medicaid benefits; trial court determined that note was an available resource on basis that promissory notes are available resources; appellate court reversed on basis that not assignable and could not be sold and could not, therefore, be converted to cash).