Help, opinions please!

My hubby had spinal surgery last year at the tender age of 29. I became the main bread-winner at our house because surgery had a 9-12 months period of recovery. It has been just over one year and hubs could no longer just sit at home. We were struggling financially and he was getting really depressed about it.

So he got himself a job, an apprenticeship which means pay is not great. And he is doing more heavy physical work. He has been doing it for 5 months now and his back is no good and he is in a lot of pain, to the point that he is thinking he cannot go on. Now, here is the deal.

I love my hubby dearly, but when he is not doing much, he is a pain in the butt. He gets really bored, that turns into him overthinking everything, that gets him down and he gets really grumpy and hard to live with. It really affects the whole family dynamics, everyone suffers because of it. He has never done anything different in his life, office jobs are not an option, he has no qualifications apart from his carpentry one, so no one will hire him... he tried sales, did not work out.... we have no money for him to back to study. I just feel like we are stuck in a rut, always struggling to get by financially.

I really can't see a solution to the problem and I am finding it very hard to stay positive. Any ideas, suggestions, anything?