You petition your Sister, let us say a visa becomes available in 2055.
HP is good for 2 years, will there be a renewal opportunity, who knows.
There is TPS but as the name says that is supposed to be Temporary
https://www.uscis.gov/humanitarian/temporary-protected-status/temporary-protected-status-designated-country-haiti
Obviously your petition is a back stop and if they are still here is 2055 whenever and in status they could file to adjust.