Yes, it is in fact true. We went back to the ArtScience Museum to bring Jakjak to the Titanic exhibition. We did this right after watching Wicked, but in his mind, it was the Titanic that he was thinking about. In fact, when he saw the white lotus shaped building, he immediately started shouting "Titanic! Titanic!".
Ever since the first time we went to see it, Jakjak has been obsessed with the ship. We thought that the second time he saw it, he would finally be content and it would die out. I guess not. He sees pieces of the Titanic in everyday things. Even the small things like how a hallway looks and how a seat or a lamp looks like the one on the Titanic. All his toys now have to be broken in half to simulate the separation of the Titanic's bow from it's stern.
We have almost completed a project together which is a paper mache model of the Titanic. Initially, it was going to be a static model, but now it is one where the funnels break off from the ship. Thankfully, what we built seems to be strong enough to take the abuse. All that's left is to put in little details and then it sets sail.
He also has a copy of National Geographic's Titanic centennial edition. He has watched every Titanic related show on History channel and Nat Geo. He even watched, and finished, the James Cameron movie of Titanic (which runs slightly above 2 hours!). Every now and then he mentions the ship, the artifacts he saw, the stories he has heard, the video clips that he has seen. This, I believe, is obsession.
UPDATE: The Titanic paper mache we have been building is completed halfway except for the four funnels, which, apparently always gets "misplaced". We now also have a 3D puzzle version of the Titanic which we recently got from BHG.
*Jakjak himself took this picture complete with backdrop. :)