There is a ton. A main character has many times where he abuses his family. He also has vivid flashbacks of his own father abusing his family. It is all very graphic.
(SPOILERS) It is implied Jack dies in the hotel after it catches fire when the boiler explodes. BUT you can argue that he was already dead, and the hotel inside him died.
(SPOILERS) at the end, when Jack is possessed by the hotel and trying to kill Danny, Danny gets through to him and Jack hits himself in the face with the mallet repeatedly, but I don’t think it’s consciously.
Many references to s*x throughout the book, (SPOILERS AHEAD) first early on and is only described after, Danny talks about his parents “doing the thing that makes babies”, after Danny gets strangled there is a s*xually explicit scene, and Danny finds a cuckoo clock where two figures pop out and start giving each other or*l s*x. That’s all I can remember off the top off my head.