Well, they can mention him but not his complete role & past.
Same as we got a reference to Beren & Luthien in the 1st episode, but we will never learn about them taking back one of the Silmarils from Morgoth - or of Beren being held a prisoner by Sauron...
It's just a pity that I enjoyed so much the chemistry of Galdriel & Halbrand in s1...
