Hmm...
Why would he be 'fine' at work (though, no one here is in his classes or his staffroom so has no idea how 'fine' he actually is)... when work is literally a day scheduled by the hour as to what he is doing, with whom, what the goals are, what needs to be covered, even down to when he has to plan and what he has to plan for...
And then struggle at home where there are far more variables, less structure, more chance of routines being disrupted etc etc.
I thought my DP was just a lazy twat - nope. He now has a DX, he is ND (Executive Dysfunction, Demand Avoidance and a few other things)... AND is sometimes, also a lazy twat!
Mine seems to think if he has spent x amount of time on a job (the amount of time he wants to spend or thinks is the right amount of time) then the job is done - then you go and look at the worktops and they're not actually clear, or the hoovering is only partially done and he can't see that.
He also believes some jobs take much longer than they really do, which puts him off doing them - he does not realise that he is including the time he spends thinking about the job, putting off doing the job and grumping about it, along with the actual time the job takes, which is beyond infuriating!
He has to work VERY hard to get into better habits and they do need to be ingrained habits to over-ride things... for example I have shown him the differences between us both making a cup of tea, which he had no idea of...
Me: Kettle on - wipe up worktops whilst kettle boils, put some bits in the counter top bin, generally look for something to do - water on teabag - sweep floor/mop floor (we have a squirty mop, not a mop n bucket mop), replace mop next to fridge, get milk from fridge, teabag in bin, milk in brew, milk back in fridge - job done.
Him: Kettle on - stare at phone/at own navel - water on teabag - stare at phone/at own navel - milk in/bag out on side... job done.
The idea that you can do one thing whilst another thing is doing its own thing... lost on him, not remotely natural in this context.
But he CAN do that same thing elsewhere, I spotted him setting his PC up to update windows and then sorting out his model trains whilst it was doing its thing - which is again infuriating.. but, it shows a lack of ability to transfer skills, more than just being a twat!