I am aware a sibling is not a disqualified person and my brother wants to pay off my father's reverse mortgage. 

Some of my siblings that have purchased houses in Utah and Idaho have said that they didnt need to make that much of a down payment, and one of them was able to build their down payment into the loan itself. 

We know there are thousands of ways to do that here in the USA, but we are trying to see if there is some way we can help my wife's siblings while investing at the same time. 

A few months before we bought this property, a kid accidentally shot and killed his sibling in one of the units.

The siblings discussed selling it, would there be any issues?

Was in the family so had to buy out siblings and needed to rent out to cover the mortgage.

He can have a lawyer represent him or another family member (just because the kids don't live nearby doesn't mean they can't help, or a sibling or other relative) or a friend.

We are three siblings, all listed on title for a home. 

I assume you are you the only sibling.  

We are financially self sufficient, so when they passed on, if there was any liquidity in the estate we would forego anything above our payback and split the estate between the two remaining siblings.