The straightforward if unfortunate answer is that we don't know if the supposed Malian expedition into the Atlantic actually took place, much less which leader of Mali might have led it, much less what happened to that leader. But, while there is always more to say, some earlier responses here address some aspects of your question, and you might like to review those threads while you wait for fresh responses to your query.

This thread led u/Commustar and this thread, led by u/MansaMontezuma, address the question of whether the fleets actually existed.

Meanwhile, this other thread, with u/amp1212, takes a look at the technological and navigational capabilities of contemporary African sailors and shipbuilders, and finds reason to doubt they were capable of building and sailing transatlantic craft.

Finally, Commustar develops their earlier post with an expanded look at the story based on new studies of Mali, in a post that you can find here.