It seems you are right. He made some enquiries with a pastor, who seems to be the fount of all Haitian knowledge, and he agreed that you can renew a Haitian passport in Santiago but not always. For example, they are not doing it now but they are supposedly going to start again sometime next month. The better news is that they will also be doing a couple of visits to Sosua (which is nearer to him) before that. They are supposedly making two visits of a couple of days each and his pastor will let him know when. What worries him is that he knows a lot of Haitians with expired passports and he doesn't know how they will get them all done.
Apparently the cost will be $200, courtesy of a loan from yours truly.