If I had to guess I'd say she was abused by the man who lived IN the home.
How 'long' it takes depends on her AND on him. If he actively pursues truly bonding with her -- and that's hard cos he has to give up 'Coke time' to PREFER to spend it with Kenya. Silly stuff like lying down on his BACK next to her, just talking to her and literally spending super quality time with her day after day after day after DAY and NIGHT --
A year is on the short side. Three if there's no extra effort and she has no setbacks.
But beyond that - if he truly TRIES to make her a priority and to let her know that ... it will change.
1. He needs to feed her. And take time to bond during that. Talk to her. Hand feed her some.
2. Deliberately put himself in almost 'submissive' postures around her. When we had Millie David spent HOURS on his back next to her. And he devised activities to help desensitize her to the things that scared her the worst.
And altho it was ME she would cling to ... HE became her savior. When we'd go in the car she was TERRIFIED of any sharp noises -- like in the South they have reflectors in the road on the white dotted strip and at the side of the road (you guys up north don't have them -- but it make it so they never have to paint lines on the roads down here) -- but they make a click click sound when you hit them with the tires. to Millie they were like gunfire.
David would have ME drive, and he'd have her in between his knees up front. Then when we approached a RR crossing, or potholes or if there were reflectors he'd say "Millie, it's going to get noisey, it's gonna go bumpety, bumpety, bumpety, bumpety, ... and then I'd deliberately hit a hole or drive over reflectors and he would repeat in a low, soothing tone bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, ... until he felt the nape of her neck relax.
That phrase bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, bumpety, became her mantra. It would soothe her ANY time she was scaredy.
Within 3 months he was her mega hero. WE had tons of setbacks -- oh my she was SO skittish. One night David poured a 30 # bag of dogfood into the big rubber trashcan we kept food in and just the sound of that kibble hitting the container -- she lept sky high and FLEW out of the room. She was a quivering mass in her crate for an hour.
This is hard since your husband has bonded with Coke. And it will require a completely different technique ... and Coke may get jealous. But if he reassures Kenya with his voice ... takes it slow and deliberately tries to soothe her and reassure her that she's 'ok' and safe ...
And then you will have to continue it -- when he gets home encourage her to go 'see Dad' and such.
THEN as time passes she will relax.
It's taken TWO years with Kee and she is only *beginning* to bond with me. I'm convinced that at some time in her life a 'big lady' hurt her. Specifically I think a big woman picked her up, probably hurt her in the process of picking her up and then THREW HER for some reason. It's taken a LONG tme, and i've had to take it very very slow, but no longer am I JUST the "food lady". Tonight she actually lingered after I ASKED if she wanted to be picked up. She did NOT run from me ... I am super careful to keep her back entirely level when I pick her up (I literally put my entire arm under her between her legs back to front) and she ENJOYED being held and I got one little kiss!!
(she obsesses super easy -- and usually she will go into a licking frenzy .. but no, I got ONE true 'thank you' kiss IT WAS GREAT).
Damage takes seconds to inflict. And ages to get over.