It really does seem like Nahlao likes to do his own thing during the day but wants the comfort of his friend at night.
Unless you want to have a cage just for "nighttime", though, which might be hard to get them to understand that during the day they have separate living spaces than at night, I believe that you would do well in separating them. Since the excessive attention from Quinn is contributing to Nahlao's more withdrawn behavior, it is very likely is an indicator of his stress. They can stay in the same room, by all means, and if it seems that they're okay with it, even move their cages close together so they can talk to one another, but I would say that they shouldn't live together permanently, at least not right now.
Even though I know they will both be upset that they can't sleep next to each other any more, I think it's important to give Nahlao some sanity time so he can fully regain his flamboyant nature away from Quinn's insistence.
As Quinn matures, he will become less "clingy" and perhaps will begin to lay off on bothering Nahlao.
Also, they can have out of cage time together since they are friends, but I believe they should just have separate cages for now.
I hope that helps!