It's very forboding how the chain broke. The chain is like the red string representing the bond between Cecil and Tia, and now it is broken.
I suspect that the spirit of light is trying to rewrite Cecil's memory. The memory Cecil is being shown is from the original timeline from the game. I guess that Cecil will be shown how he meet Heronia and become "happy" next.
I hope that it will not go memory loss route. It's too heartbreaking. I am hoping that Cecil, after being shown memory with Heronia, will resist the rewriting and break free, possibly all within the next chapter. Or else I will have to stop reading for a while, at least until his memory is back. (I did the same thing with that webtoon with memory loss)