Because that's what B-fly's post said....
If an owner has to move out of the house for a certain period of time--to a nursing home or a hospital, for instance--that absence could be enough to trigger the repayment requirement, Investopedia states. With an FHA reverse mortgage, the owner can spend up to 12 months in a nursing home without the debt coming due.
Maybe I misunderstood you. I thought you said you were concerned that if you had to leave your home for awhile, they could make you pay it back.
It looks like you can be gone up to 12 months before they could do that.
If you have left your home because you can't take care of yourself for an entire year, and are getting up there in years, chances are you're not going to.