Milk, I'm lowkey super invested in your Will headcanon. If you don't mind, I have a few questions:
1) Has Will ever contacted his mother in the institution?
2) Does she feel guilt or miss him or has she tried to contact him in some way?
3) How does Will's thoughts of possession manifest?
4) Was the assault from the stepbrother invasive? Is this okay to ask? *why I'm in anon, I don't want to sound like a creep, but I was very curious for details because I think it makes so much sense with canon.
5) On the same note, could you specify the abuse from the cult leader guy?
6) What do you make of the stag Will hallucinated in canon and how it could connect to your hc?
7) Do you think Will has destructive coping mechanisms?

Sorry if it's too much you don't need to answer, but also if you ever want to expand on the headcanon, i think it would be so interesting!

Oh wow, hi, anon. It’s okay to ask, although I’m not sure it’s okay for me to answer that outside the realm of fanfiction, which these darker details could be explored in a way that is usually dismissed as “just fiction”. It might be jarring for me to say these things here, but I’ll give you some overall thoughts.

1- I think Will has lingered with the institution’s number in his hands many times. He wanted to contact her, but never did.
2- I think she is too under her delusions to see him as simply her child.
3- To me, the way he constantly hallucinates himself with the antlers, or somewhat blending into Hannibal, is a sign of ideas like possession.
4- It was intrusive. I see a lot of signs of eroticized trauma in Will’s behavior and the particular ones I observe are tied to physically intrusive abuse. Overall he sexualized Will and introduced him to sexuality much earlier than he had the capacity to absorb and understand it, leading to confusing emotions regarding sex.
5- I don’t think Will’s hallucinations with boiling water, or the many times he’s squirming in bed were made up during canon. I think he is reenacting earlier experiences related to this man. He would tie him up, force him to engage with others (but by manipulating, not directly forcing, always maintaining a guiltless image), things such as boiling water, burns, electrical shocks, etc. All disguised as sexual experimentation and alternative therapy.
6- In the books, the Stag is Hannibal’s, but since they made no reference to that on the show, I believe the Stag then is the same as Hannibal in the book: Will saw a stag when someone died, maybe when he killed his dad there was a Stag outside his window or something. I believe it is tied to a “guide” type of totem. In Mizumono it dies because the Stag represented an innocent energy, and Will’s “innocence” (in regards to him always lying to himself about wanting to kill only bad people and not admitting his desire for violence) was gutted by Hannibal.
7- I believe he is an alcoholic but they cannot show this directly in television in a main character, specially considering all the things the show was already getting away with. But it is shown a bit in season 3 B.