He wouldn't be doing this if he didn't have you to do everything from paying for the roof over his head and the food on the table to doing the washing.
From experience, those couple of months goes to a year to eight years before you know it. And for all of that time, you will be carrying everything without the slightest chance of being able to rely upon him for anything at all, because it'll be 'putting pressure on' or 'bullying' or 'you wouldn't treat me like this if I had cancer'.
And then there's the 'relapse' at the first sign of things not being perfect if he did get a job in the new industry. Slightly too direct boss, bit of concern about missing a deadline? He'll be back off sick saying it's too much for him to bear. Because being at home having somebody else take care of the mental load, the financial load, the housework, shopping, cooking, planning feels safer. Being able to stay up all night and sleep all day without any responsibilities, tasks or reason to change it means he will then be 'too tired' and 'didn't get around to it' for training, applications or anything else. He'll likely take specific steps to deceive, such as setting an alarm for ten minutes before you get from work so he can claim he's been up and busy all day. He'll be too tired or stressed to do any housework. So the place will, unless you do it all whilst he lounges around being delicate, look like a dump. He'll be deficient in vitamin D, his mood will drop further due to this, his energy levels will be through the floor, joint and bone pains, he'll be physically unfit and struggle with such things as sitting upright or walking/leaving the house unless it's something he fancies doing, at which point he'll do that whether you like it or not. And then expect a week in which to recover whilst you slog on making this all possible for him.
Regular work, even parttime, has advantages far beyond money. It means regular sleeping patterns, activity, daylight, thinking and interacting with other people, fresh air, keeping good personal hygiene, looking smart/dressed appropriately. It's a reason to maintain good habits. And it makes the career changer have something useful on their CV rather than look like they were unofficially sacked for incompetence/possibly spent the time in prison/rehab/drinking and lazing round the house.
For his own health, the longer he stays out of working environments, the harder it will be to go back - so he needs to work. Now. Not in the claimed year, as it'll never be just a year. But now. Anything - cleaning, driving, office temping, anything that gets him out of the house and doing stuff that's useful, brings money in and avoids a massive gap on his work history or having no reference for eight years when he finally decides he can't get away without working any longer.
Or you send him back to live with his Mum and claim benefits. Chances are that he'll find something pretty sharpish if he thinks you can't be manipulated anymore, and if it is over, he'll do it then because he hasn't got somebody to parasitise. The prospect of having to claim benefits and comply with jobseeking agreements where if they don't comply, they have no money for food tends to focus the mind somewhat.
You don't have to do this because he demands that you do. Not because he threatens anything terrible or tries to guilt you into compliance. You DO NOT have to carry this weight.