Somewhere in my photo collection I have a photo of Milly (budgie) preening Olly (lorikeet) back before the aviaries went up and they had their own mates to preen. From what I saw of Olly and Milly's relationship they were both able to sort things out if one pushed things too far. Olly isn't a real ADD type lorikeet though and Milly is reasonably placcid. Having seen my two I can see how it can work.
I think it's great that the 2 of them have found a mateship. I wouldn't discourage it if they're happy. You know the safety stuff to watch out for.
