I don't think it's CTE... I know it's trendy to jump to that when a football player does crazy poo.
Chandler has Bi-Polar disorder. Has for a long time. He had a manic episode when he was in NE...
Often BPD can be co-morbid with mild/borderline schizophrenia and Chan is exhibiting strong indications of this.
It spirals.... snowballs...what starts as a single person maybe saying something shady...in 20 or 30 minutes has grown into a guy locked in his bedroom with a gun because the entire state are covert nazis out to get him and they have been recording him for years...and all the proof is right there on his own Instagram page.
Friends and family so often blow off the early signs because "he just gets like that sometimes"
Often a person's logical thought is constantly telling them that what they are feeling couldn't possibly be real and that's the only thing keeping them from going over the edge.