I've meet him but the game requires lesser crews (Idk how many crew shouldn't be recruited) on the ship in order to actually find him. In my case, I didn't recruit Rylan (or kill), Bradley (or kill), Skru'Vaks (or skip) and Phoenix(or skip) to actually recruit Isaac.
Isaac serves just like Hakkan, additional crew for missions and tasks. He is not useful yet, in this version.