I think we have new respect for the gravity of the situation, but it was a drag for that gas-bag of a planet.
Your post hits on the key words. Gravity and drag.
I dont mean to get all geeky, but there is a fundamental question that I dont see addressed here. Correct me if I missed it. But for the planet to spiral in, one of two things has to happen:
A) the suns gravity has to increase, which means more mass has to come from somewhere (i dont know how that occurs), or
B) the planet has to encounter drag in its orbit, and a lot of it for a spiral to occur. This implies an atmosphere in space, which is normally a vacuum. Without drag, the planets orbit has no reason to decay.
I am not saying this is a non-believable report, but I am skeptical without some theory explaining it. Are they saying that space around this gas giant is as dense as an atmosphere? If so, it would be a 1 in 1 trillion chance that we just happen to be looking at this 1 in a billion stars at this exact moment in time to see this event.