Aldo Clemens is dead.
Even Booth hasnt talked to him in over a year.
Brennan blames Aldos decline on post-concussive symptoms, the kind that present themselves years after the initial trauma.

Credit: Kevin Estrada/FOX
He usually does, doesnt he?
In that sense, and in a lot of senses, Aldo is a mirror to Booth.
They both take on the problems of the people they care about.

They both have strong beliefs, but Aldo stopped taking comfort in them.
Booth is a gambling addict; Aldo was a drug addict.
Booth got a brain tumor; Aldo got a degenerative brain disease.
He isnt better than Aldo for surviving.
He just got lucky.
Remember when Brennan used to worry that she didnt know how to be there for Booth?
Brennan is great here with Booth.
Booth attributes that to her.
In Booths eyes, everything that separates him from Aldo comes down to Brennan.
Booth regrets not doing enough to keep Aldo alive.
He doesnt want to be told to forgive himself, and he doesnt have much use for Carolines sympathy.
Brennan gives him a way forward when she tells him that its healthy to get revenge.
So lets get to crime-solving.
Intern-of-the-week Jessica spots needle marks on Aldos toes, which Hodgins swabs for heroin residue.
Angela then runs that drug cocktail through the DEAs local database to narrow down a list of possible dealers.
Can you really tell handedness by the way someone parts their hair?
Thats actually called harassment, Jake protests.
Booth says, in the voice he might use when Christine learns a new word.
Dont mess with Booths friends.
NEXT: Why did it have to be rats?
Booth rips Jakes video doorbell right out of his wall to check the story.
Theres evidence that rats were eating Aldos ribcage long before he died.
What we have here is a gruesome torture method that manages to double as animal cruelty.
(Brennan on being blown up: It was unpleasant.)
Someone looking for revenge and not Booths kind of revenge is coming for him.
They probably wont stop with Aldo.
If this is the big reckoning ofBonesfinal season, I have some reservations.
The timing comes out of nowhere (Why wait almost 22 years to take revenge?
But there is something cyclical about it that I find fitting.
He has, with her help.
Once again, Brennan makes all the difference.