I don't think the Dems will lose the black vote because of Haiti. Sad as it is to say, the welfare state won't go away that easily, like a lot of people (black or white) at the socioeconomical bottom of the totem pole, they will vote for the party who helps them (i.e., gives them free stuff using other people's tax dollars).
I don't even know if Haiti will make a dent, at worst they'll just blame it all on Hillary and keep the welfare state running.
Maybe think of a different tactic? Like an end of flooding ghettos and hoods with guns and drugs? Those product that are ripping black communities apart aren't produced in the hood, but they're finding their way to the hood. Expose how.