It's one of the rules of this board that topics be given descriptive titles. As well as having more chance of piquing people's interest when first posted and increasing your chances of a response, it will also help people doing later searches on this topic. Hence Phil's cry of anquish at the 'Small Question' title you gave the thread. I've changed it to something more descriptive.
Jack, I don't know if there's any way to check this out. My understanding is that Harland & Wolff has no employment records from that period, and that would make it very difficult to verify. Even if it could be verified, there's no way to know or even guess which ships he worked on. Workers tended to be sent as and where needed for a particular job and were seldom if ever wedded to a single ship.
Jack, Michael is quite right. Quite some time ago, H & W made it clear that they have no records of employees of those times.
You may find out something about the man from public records held in Belfast. They just might give you where he lived and what he did. You might then at least know if there's a chance he worked on Titanic. Sadly, this sort of thing is best done on the spot.