Grand Mother Silk is said to have been very controlling of her children, as well as attacking the player character whom she seeks as a surogate daughter.
During one section the player character's cloak is stolen and she appears "nude". However, she just looks like a stick figure, and it is not in any way presented as sexual.
Minorly discussed. Player character mentions that she has outlived the natural lives of many previous partners due to her unusually long lifespan in an optional journal entry.
Implied. During a memory sequence, we are shown that the player character has very unclear memories of her mother, suggesting abandonment. This is further discussed in the previous game: Hollow Knight
Discussed and subverted. A character is shown to be severely ill, and expects to die from his illness. He is later shown to have been crushed to death by falling debris, partly due to being too sick to move.
Spiders are a central theme and spider-like creatures appear throughout. However, they are highly stylised and I know of at least one arachnophobe who has played it without trouble.
The hospital area features pits full of needles as environmental hazards. Some items usable by the player character include needles she can inject herself with or use to extract substances from enemies, although using them is entirely optional.
It is a major theme and there is a lot of religious imagery/discussion throughout. The actual religion is fictional but bears some superficial similarities to Christianity.