Hell, do you really want to work? Tell Mr. 15 that he likes to eat. And it’s probably appropriate to mention packs of starving wolves at this juncture.
You might bribe the teen with driving lessons, or some other privileges, such as a later curfew or more outings with his friends. The other kids can get other bribes.
I suggest drawing up a list of things that need to be done while you’re at work, by ALL the sibs. Things like laundry, dishes, basic housekeeping, and such. Assign chores specifically to each child, and check them off each day. Make sure that the kids understand that they WILL have to do basic clean up each day. Even fairly small kids can do things like mix up Kool Aid, unload a part of the dishwasher, and sweep a floor. The kids who have completed all or even most of the tasks get the bribes, errrr, rewards for the week. At the end of a month of good behavior by EVERYONE, then a larger treat for working together. Video games, movies, whatever, it’ll be cheaper than babysitter fees. Plus, since you’re working longer hours to bring in money, you’re going to need some help with the housekeeping. And these are skills and habits that the kids need to learn anyway.
May I point out that I was cooking full dinners by the time I was 15? Not just stuff like Hamburger Helper, but a meat dish, two or three vegetable dishes, and cleaning up afterwards. Mr. 15 can at least do things like peel potatoes and cut them up and start them boiling, and prepare a salad. And the younger kids can help. Again, you are going to be exhausted when you get home, and you’re going to need some help with meals as well as housework.
Make sure that you don’t give them too much to do, though. Kids need free time, as well as chores.