Linus is doing much better after his "misadventure". He has really calmed down, to the point that his cage can be approached without him freaking out. In fact, his food and water can now be changed with little more than him stiffening his body with worry. A large improvement from flinging himself against the bars! He still does not play much; in fact, he has only been caught playing once, though he does also chew on a manu mud block somewhat frequently. I have filled his cage with what were favorite toys of his, so I am hoping he will "re-discover" them again soon.
He has started to sing again though! All day long he can be heard: whistling, talking, giving kisses, and imitated every possible noise he can in general! It is wonderful to hear, he was such a joyful fellow, and his long silence has was heartbreaking.
He also seems to be interacting some with people, which is wonderful. I have been told that he even gives kisses when someone comes the room now!!! I am hoping he will settle back in with Ava. When I first had him, he was very good friends with the budgies, and just loved them. Ava is quite lonely now, without a friend, and Linus I know does better with the security of another bird near him.
Edited to add: As I had hoped, Ava and Linus quickly took to each other, and are no longer the two lonely waifs! The have become totally inseparable, following each other around all day; Ava offering Linus support and confidence, and Linus simply giving Ava a good friend to confide in, as well as someone to boss around!