Presumably the loan period is quite long, and someone has some amount of income, so monthly payments are tiny. You can keep refinancing indefinitely until you die, after which your descendants can do a one-time liquidation (paying no cap gains tax) to pay off the balance.

You never have to pay back the loan yourself. Just make small monthly payments and refinance until death. This is actually a pretty widely-exploited part of our tax system, for very high net worth people.