Brand is alive and seems to be sane. The Unicorn blocked him from using Trumps or anyone from using his Trump for a time. (She was still pissed off about that trying to destroy Creation thing, apparently.)

Brand is busy with his own problems but willing to help out here and there in the hopes of changing his status vis a vis Amber from 'shoot on sight' to something better.

His project involves moving spirits from one body to another.

His 'associates' in Chaos are Fantasia Frost, Kwai, Sandhya; Brand's gentleman's gentleman Deeve looks after their needs.

Update: Brand's project was the re-embodiment of his wife Jasra, whom had been absorbed into the Fount of Power in the process of healing him. Deep attunement to the Fount is what drove him mad. He and Jasra have a 17 year old son named [Rinaldo]?.

He found most of what he needed in Chaos in the Royal Archives there after making deals with the Archivists to help out in their part of the succession struggle. He had to leave when the Serpent woke up to battle some other monster released from the depths of the Archives -- not his doing, he says.

He got the Family's help by offering to grow new bodies, fast, for Thera and Delwin, who were little more than heads and spinal cords at the time. With the help (probability adjustment) of Julian, Delwin, Thera, Samantha, Archimedes and Merlin, the knowledge gained in the Courts of Chaos and the full power of the Fount (massive amounts of user-friendly magic), he re-created Jasra's body and put her spirit in it, paid off Fantasia Frost by killing a captive Chaos Lady (not a Logrus master) and installing Frost's spirit therein, then fulfilled his agreement with the Family by using other captive Chaos Lords, killed on the spot, for raw material and making bodies for Delwin and Thera. Brand's sanity was slipping badly at that point but he was encouraged -- threatened -- into exhausting the last of his Fount charge as agreed.

Brand moved his family away from the oh-so-addictive Fount.

He's trying to establish an amiable relationship with his son Archimedes, for whom he had had -- when mad -- plans that no longer made sense.

The Unicorn is no longer blocking Brand's Trumps or, presumably, his use of it. Maybe she's too busy.