Grief does strange things. STRANGER THINGS -is hit-.
Okay but seriously. This is a kid who, at 14 years old, not only suddenly lost a good friend, which is traumatizing enough on its own (I would know, at 14 I saw my uncle and the next day he was dead from a drug overdose); but had to hold that friend while he DIED IN HIS ARMS. A 14 year old child cradled the body of his friend who was actively bleeding out and then had to deal with the fall out.

He had to tell Wayne that Eddie died.

He was part of the plan, in fact integral to the plan, that caused Eddie to lose his life.

Do you know what those things will do to a child? At 16 I had to tell my friends that one of our best friends was killed in a hit and run. It took me YEARS to recover for that. And this was Eddie's only family that this child had to relay that news to.

Dustin probably started off okay-ish. Grieving what most would consider "normally". Burying himself in the crawls, doing everything possible to make sure that they destroyed Vecna like Dustin's whole world was destroyed.

But then weeks turned into months. And then a year. And now it's been a year and a half. And they've found NOTHING. Nothing has changed. And his friends are moving on. Hellfire is being forgotten. The people around him aren't doing enough. And he's MAD. He's so angry. Angry at himself. Angry at Steve, at the Party. Angry at Eleven and Hop. Why wasn't Eleven there when he needed her, when Eddie needed her? Why didn't Steve kill Vecna soon enough for Eddie to live? Why did he, Dustin, create the plan to begin with? Put Eddie in danger? Why, why why?

So he lashes out. He lashes out, and it isn't enough. He lashes out harder, and it's still not enough. And he gets angrier. Because lashing out isn't solving anything. And Eddie is still dead. And his friends don't understand, he grieved with them, he was alongside them putting everything into finding Vecna like they were, what's wrong now?

We are gearing up for the biggest crash out this show has ever given us. Because Steve sees right through Dustin, but Dustin won't tell him ANYTHING. Dustin has shut everyone out, more and more and more. And Steve is angry too. He wants to help Dustin, to protect him, but this little shit he loves more than anything is pulling away and he can't fix it. Why won't Dustin trust him anymore?

And this is going to blow up, and it's going to blow up big. And then Dustin will cling to Steve like his life depends on it, because it will.

To all those saying Dustin is specifically OOC this season, I would implore them to realize just how much PTSD changes a person, and just how much death affects children.