T.B.
We just moved back from Amsterdam after living there for 2.5 years. It took my now 7 month old 2 weeks to adjust. It just takes time. Sounds like you are doing everything right. Make sure you get outdoors whether the weather permits or not and surround him with loud noises. Also try not to sleep in which will further mess up his schedule. Awake at a normal time, nap at a normal time and go to bed at his usual time. Even if he cries for a bit at least it is retraining his internal clock. Again it just takes time and know there is light at the end of the tunnel. Good luck!