Can I tell my boss I refuse to train the apprentice? I'm the only technician.

I'm the only technician in a small workshop. I've worked alongside the apprentice for 12 months now. To preface, it's a high end tuning shop so quality of work is insanely important.

When I first started with him, he wouldn't listen, wouldn't follow instructions and if I tried to explain things to him, he'd get angry, ignore me or just run away and hide for a while. I kept telling him to torque the sump plug but as soon as I'd turn my back, he'd just tighten it by hand. I had one car come back because he'd over tightened it and dented the sump. Everytime we did brakes, I'd tell him to 'clean and grease' but when I'd check over his work, he hadn't done either. I told the bosses "it's like he doesn't want to learn" He told the bosses "I can't learn from someone I don't accept"

Bosses told him to pull his head in. He has to take me seriously. If he doesn't change his attitude, he's gone. Kid spent the next three months cleaning the workshop to avoid me completely. (He said he thought I wanted space and he did that for me but I don't buy it)

I asked the bosses if I can do his reports to the MTA from now on. They said yes and told the kid "she's doing your reports from now on so you better prove yourself to her or you're gone"

He was the perfect apprentice for a few months. He actually let me teach him how to service. He was looking things up, torquing things to spec, cleaning spilled oil and brake fluid. I was well impressed and told the bosses he's ready to work alone.

First they gave him spark plugs. He didn't look up the torque settings and just guessed. (manufacturer is adamant to torque everything to their standard or it'll cause running issues)

Then they gave him a service. He didn't look up anything. Guessed what oil and how much, guessed the torque settings for the sump plug, didn't test the battery or check the spare and didn't read the placard for tyre pressures. He also asked the boss if someone else can check over his work. (the owner or manager and not me) He knew what he was doing. You should have seen his face when I came over to check his work. Kid was ANXIOUS. I asked him what he torqued the sump plug too, he said 30nm. I said, is that what it said when you looked it up? He said "no, that's what -the owner- told me." He never asked the owner. I asked if he tested the battery (knowing he hadn't) he said "yes, it's good" I asked him where the battery is. He didn't know.

The MTA guy came in and I said "he isn't trainable" The boss said "maybe he'll change" I said "it's been 12 months and he's on his third last warning. How many chances are you going to give him?"

Usually when I train apprentices, I can trust them to do basic jobs alone within 3-6months. Because they look shit up and torque shit! I don't have to check over every nut and bolt because they've tightened everything perfectly and put in the right oil. It's been 12 months and I STILL can't trust him. It's infuriating how closely I have to watch him because he won't follow instructions. He's making a conscious decision to not listen.

MTA guy says "if you don't think there's any hope for him, I'll transfer him to another workshop. If they don't like him either, then he'll be kicked out of the MTA."

Management says "let's start with a clean slate. Everyone deserves a second chance."

I said "you mean fourth chance"

The kid turned on the waterworks and cried to me "I want to prove to you that I am teachable." I said "you've had twelve months" He gave me some bullshit sob story about his mum and how he 'looks up to me' and he's "so sorry for fucking up" and he "never said I can't learn from someone I don't accept! I never said that!" He cried even harder when he said that. I asked "why didn't you do that service the way I taught you? That was your opportunity to prove yourself" He said he was awake ALL night thinking about it and feels like shit and he doesn't know. 🙃

He just won't stop lying. I don't trust a word he says. He's proven to me time and time and time again that he can't be trusted. I told the MTA guy he's not trainable. I told the owner I don't want to work with him anymore but management says "give him another chance".

Tomorrow I want to flat out refuse to work with him. Would I be out of line?