Color me puzzled. (Not for the first time...)
Why would Baby Doc return to Haiti? I can only think of three reasons: he thought he had a base of support that would let him take a role again, even if only a token role as "big man bringing some aid"; he is dying and wanted to die there; or he was delusional about what the reaction would be. It didn't sound like the French were pushing him to leave, and I gather he still had a few francs in his pocket (Wikipedia says he had fallen on hard times, but I'd bet he's still richer than me.)
I wonder if he had voodoo advice before coming.
UPDATE: It was suggested that he might have hoped for enough disarray to be able to come in and leave unmolested after a few days. It seems the Swiss have a new law to prevent the release of disputed maybe-national funds to fugitive leaders. If Baby could persuade the Swiss that Haitian inaction meant they weren't serious about arresting him, then he wouldn't be a fugitive and he could lay hands on the money. Not a risk I'd care to take...