In Dilbert, he’s called Wally.
Around here (a military office), I hear the acronym FIGMO a lot. “Fuck It, Got My Orders”
“treading water”
RIP, as we say in the government. Retired In Place.
I thought goldbricking had the connotation of milking an injury or illness to work as little as possible, rather than the no-longer-give-a-fuck attitude of the OP’s boss.
I keep checking back to see Monkey Saber’s reaction, but I guess the monkey’s just phoning it in…
Middle management. 
Passive-Aggressive? Sour Grapes? Half-Assed / Half-Hearted? Shirking their responsibilities? Indolence? Not pulling their weight? Slackitivity? Senioritis? Fucking the dog? Screwing the pooch? Throwing you under the bus? Flying by the seat of their pants? Finger up their ass?
“What are they going to do, fire me” was my favorite phrase the last 3 weeks of my old job before I started the new one.
Get a relative or close friend who has a lot of hiring decisions. I have heard several stories of people hiring family members and friends as ‘consultants’ to do that.
Another military term probably not applicable here:
REMF (rear echelon mother fucker)
At our company we refer to people like this as LB=Lazy Bitch!!! 
The corporate-speak term I’ve heard is “disengaged”, but that can apply at any time, not just prior to a transition.
First thing I thought of was “shagging the boss” who, in OP situation, has presumably now left the company.
To the OP: Well, is any of these the term you had in mind? Enquiring minds want to know.
work + slacker = whacker
I think that’s more of a term for a type of non-combat job and the people who do them. Not a judgement on how well they do it.
I propose “shredder guy” in honor of lazy gov’t workers everywhere.
That was what I was going to say.