Baldur's Gate 3 will have players exploring many different regions of Faerun in an attempt to remove the Illithid parasite from their head. In Act 2, players will reach the Shadow Lands and the sanctuary of the Last Light Inn.
Within, they find an unconscious man who is suffering from the exposure of being in the shadows for too long. Through a few hints, players can pick up that this man has ties to Halsin's personal story. No matter your motive, here is how to wake Art Cullagh from his coma-like state.
Finding Art Cullagh
Upon entering the Last Light Inn, Art is found in the room on the first floor, off to the left on one of the beds. While he is in a coma-like state, he will still be muttering a few nonsensible words. After making a few different skill checks or checking his pockets for a hint, you'll figure out you need something personal of his to bring him back and that he is a musician. These hints will ultimately point players to the House Of Healing.
The House Of Healing & Art's Lute
The House Of Healing can be found by traveling north from the Moonrise Towers fast travel point or going south from the Inn and heading west once reaching the town's square. After entering the House Of Healing, you must either talk your way past the sister or fight and kill her. If you fight her, kill her quickly, not letting her escape the back room, and alert her allies.
In the next room, you'll find Malus Thorm, along with four other sisters. It is possible to fight Malus Thorm to proceed, but he is a very challenging fight, and there's an easier way to handle him, depending on a few dice rolls. Tell Malus you're "A student, yes. Do please enlighten me." and pass the next check to be presented with two options. You can tell Malus the sisters need to practice their techniques on each other or a master. Passing each check will have the sisters killing each other or killing Malus himself. Failing either check will begin combat with everyone against you. Having the sisters kill Malus is the best option, as you'll still receive XP, and the sisters won't be hostile after his death.
After killing Malus Thorm, however you see fit, loot his body to find a Lute. Take this Lute back to the Inn and begin talking to Art to be able to play the Lute for him. Doing so will wake him up and open up the next quest in Halsin's journey.