First, you and your wife need to get on the same page. The way I read this, each of you has valid points, but each of you is looking at this too black and white (aka right vs wrong). This is mostly gray area.
Your wife isn't wrong to want him to better himself, but if she's implying he needs to map out his entire life in the next 3 months, this is insane. Does she know the average person changes careers (not jobs) 4 or 5 times during their life? What matters most now is he commit to something and that he see it through. Also, on a degree, she's not wrong about it helping, but it doesn't have to be the 1st thing he does. More and more people are getting that degree to help them advance in the career they've discovered they really like. She has it backwards.
As for you, you need to be more realistic, meaning push a bit on his motivation. If something radical doesn't change, he's not going to get career inspiration flipping burgers. What you don't want to happen is the increasingly common nightmare where years go by and suddenly he's 26, depressed and with options starting to narrow.
If I were you, I'd focus on a cert course. In the US, these are of short duration (a year or so) and in major fields, like healthcare or IT, there's a nice career ladder for him if he wants it. They offer placement assistance. So go for a low level cert, and tell him that you want him to commit to it and to finish it.
Finally, you seem too laid back about the idea he hates studying. I'm not sure exactly what that means, but he's not going to function well as an adult if he resists reading and learning. Even in jobs I've loved, I've still had to learn about stuff I didn't, and this is the real world.
· 3 weeks ago