I can't see T1 closing in the next five years, Ozzy. I reckon at least 7-10 before they shut it down. I understand the next T2 pier won't be completed for another three years, and they'll likely require a 3rd T2 pier to be operational before considering the shutdown of T1.
If I recall correctly, Piers B and C from T1 will remain operational and connected to the new T2, even after the T1 decommissioning. Both of those piers are in dire need of a refresh, particularly pier B which is now 60 years old.