I have a specific txf This Is Not Happening / Deadalive headcanon that after Mulder’s body was found and Scully failed to find a way to revive him, she would not leave his side, and the only person able to bring her around is her mum.
This is probably something many fans have imagined, but I need to write it down, get it out of my head, because it’s haunting me like a song whose lyrics I only partially know but that somehow becomes an earworm.
I see Scully walking back to him, angry but silent, ignoring any attempts from anyone to talk to her. Maybe she kneels next to him. Maybe Doggett or Skinner try to get her to come away so he can be taken care of (by paramedics? Agents? Whoever would be responsible for properly removing a body in that situation).
But of course she won’t be moved, she doesn’t acknowledge any of them. Sometimes when I imagine this, she’s crying, sometimes she’s not. She goes with him, wherever it is, for now - while she can. She won’t let him go just yet. She won’t let him be alone after so long apart.
Then she’s in a morgue (or wherever it would be appropriate to send/keep Mulder’s body? I assume he’d be flown home so this takes place before that, in my mind), and she’s sitting vigil by him, maybe holding his hand, sometimes talking to him, but too softly to be heard by anyone.
In this headcanon, it’s Skinner who realises that they need Margaret Scully, and he sends for her. It’s Mrs Scully’s presence, maybe her gentle “hello sweetheart” or just “Dana” that gets through to her daughter, who at that moment, if she isn’t already, begins to weep.
Maybe Scully says “he always comes back to me” or “I don’t know how to do this” or “I never got to tell him” or maybe she recounts the obvious signs of torture or injury she can see. Maybe she explains that she is responsible for his ‘estate’ (that for all intents and purposes, she is his next of kin) and that she won’t allow an autopsy. That he’s suffered enough, that she will not let anyone touch his body again. He deserves to rest.
Whatever the details, it’s Mrs Scully’s grief (not equal to Scully’s but authentic and tangible and a reflection that Mulder is beloved by others) that allows her daughter to take the first, painful steps in the direction of saying goodbye to Mulder, acknowledging that This Is, In Fact, Happening.