The loan requires no monthly repayments, has no pre-set maturity date, and is "non-recourse," which means that the buyer(s), their heirs, and their estate are not responsible for any loan balance that exceeds the value of the home at the time it is sold to repay the loan.
http://www.hecmpa.com/FAQ/#Are-HECM-for-Purchase-loans-more-costly-than-other-types-of-loans