A lot of the parents in the franchise are abusive. In this book in specific (along with the ones that appeared in previous books) are introduced Sirius' mom and Hagrid's mom. Both of them were abusive mothers on their own ways. Sirius' mom hated him and constantly insulted him, whereas Hagrid's mom mistreated Grawp
Up to interpretation. Snape's personality was based on an autistic person and various of his traits and part of his behavior can be interpreted as autistic. Since this was done without research and not on purpose, it could be considered misrepresentation.
Nevertheless the character was never confirmed as autistic.
Snape is described as restrained by "invisible ropes" by Sirius using Impedimenta against him. A bit later on in the same chapter James uses the Levicorpus jinx against Snape.
Not sure if it counts, but it's revealed that Severus Snape was bullied and abused during his years at Hogwarts, while later on he's been shown mistreating the Golden Trio (Mainly Harry)
In Snape's Worst Memory, James Potter jokes and has the intent of removing Severus Snape's underwear in front of the rest of the students while he has Snape restrained and hung upside down. Nevertheless, it's never shown if James actually removed them or was stopped before doing so.
Not shaving but cuts. It's described that Harry and Hermione ends up with several cuts on their arms and legs after coming out from the Forbidden Forest.
Hagrid is mentioned to have bleeding cuts on his face every time he appears after he returns.
after the dementors incident in the beginning, dudley vomits, the twins develop pastiles that can make people be sick, people do so throughout the book, at the kind of ending of the book, when harry has his vision he vomits after he wakes up, but it is just mentioned and not described
The "closed ward" of a hospital appears to be for mentally ill patients. We meet a few longterm residents. The scene takes place on Christmas Day and the patients are being visited by their families.
Depending on how you view it, both Snape and Bellatrix who do exhibit signs of depression and plain ol’ insanity (respectively) are both mildly violent.
ATYD is not canon, it's a fanfiction written by a fan and, therefore, can't be used as a source for information. That being said, a character dies, but said character is not stated to be homosexual, it's just the fandom that considers him as such.
Not exactly a nude, but during Snape's Worst Memory it's said that he's pantless (Without trousers) and his legs and underwear are somewhat described. James has the intention of removing the underwear but it's not shown if he does it or not.