How do I get Vivalzart to listen to me?

Hint 1 of 4:

Have you talked to Kael about him yet?

Hint 2 of 4:

You'll learn that Vivalzart needs a mushroom to put him to sleep.

Hint 3 of 4:

Vivalzart is sure funny looking.  He needs someone else who's funny looking
to pay him a visit.

Hint 4 of 4:

Only Winkle will be able to knock on his door.