To help him you really need to make sure he tests regularly to help prevent blood sugars going too low.
Its possible the amounts of insulin he is taking may need adjusting, or that he might be overcompensating for highs which is easy to do when you are new to it. (and even after) There are a lot of things that can make your blood sugars go up and down, including your own body, so mistakes are frequent till you get the hang of it. His lifestyle is probably making it more difficult for him, but its not all his fault, it is often hard to get control even at the best of times.
He doesn't need to worry too much about going a little high, as long as it doesn't make him feel ill, and he doesn't have ketones in his system, he can work on lowering them carefully when it is a better time, such as less stress or work that could drop him too low.
It is possible that the hypos could be making him weak, dizzy or confused etc, - 2.4 is defiantly the sort of level that could do that, and he might take a while to recover. But unless there is some other reason why he needs extra time, several hours seems a little much to me, he might be OK without such a long time if kept an eye on and he keeps an eye on his blood sugar levels. You didn't say what kind of work you do, but if it is using machinery or anything else that requires attention then he is probably somewhat justified, as confusion and lack of concentration are often a problem, but a doctor would be better to advise.
As long as he takes enough fast acting sugar to get his blood sugars up to safe levels, then has something to eat that will help keep his levels up and tests after to make sure he has taken enough to stop dropping further he should be OK. I'd probably test every couple of hours if I were in that situation, its better to suffer a few more pinpricks than needed than going into an hypo. And in his case, the less chance of him losing his job because of it.
4 months isn't a long time to get used to having such a complicated and life threatening disease - its not surprising he's having it tough. He may need to learn more about it and how he can better manage it, and then practice what he has learned. The anxiety about going to high or too low can cause you to over do things as well, so he might need to slow down a little and be conservative over correcting his blood sugars. Even if he is talking to his Diabetic team, its always a good idea to learn a little bit about it yourself, as their time is limited, and you can learn at your own pace, so you could point him to this site, or the library if he hasn't enough cash to go on-line at home. Hope he gets over his rough patch.
You sound like a nice bunch of people to help him out as much as you have, I hope it gets better for you as well.