One thought that occurs to me here.

You can shield them from harsh economic realities and the stress which that induces, but I sort of wonder if that is completely necessary. 16 year olds are quite resilient, and they are at an age where they are beginning to choose their path, and re-affirm their own values and goals. I humbly suggest that exposure to harsh economic realities might actually be a service to them. While it may be stressful, it may also be formative and motivating. Maybe this sets them thinking in their minds "It's rough out there, I can't afford to mess around. I'm not going to let myself be put in this position and I'm going to get my degree and become a [insert high paying profession] no matter what. Nobody is going to stop me."

I think to some degree I was shielded from a lot of the stresses of adult life in my youth, and I don't think it really benefited me. In very basic, practical ways, I'd have liked to have had more awareness of what people older than me have to struggle with daily. That's wisdom, and I think that it can easily outweigh the price.

I remember after my mom divorced it was very rough for us. A bit after she had a relationship that she had to end because she felt the guy she cared for had a drinking problem, she didn't want that around her kids, so she ended it. One afternoon I came home and found her crying, holding a letter from him opening up his soul and begging her back. When I asked what was wrong she showed me the letter and asked me to read it, and wanted to know what I thought, and what she should do. It was really heavy, but that moment became a turning point in our relationship where she was my mother, but also starting to be my friend. It was changing to be let into her world of adult troubles, to have to step up and formulate a mature response that reflected my views, and to be seen as the beginnings of an equal in a small sense. I took it very seriously, and it had a positive impact on my development. It's amazing what having another person you care about depending on you can do, no matter how small the issue seems. What you view as stress for your sibling(s) could may well be an opportunity for growth with you that they will cherish.

Anyway, just a small thought on that. Hang in there OftenBen, I'm an older brother too. Sometimes when you've got something difficult to communicate to someone, you just have to muster the determination, pull the band-aid off, and deliver the news with honesty, directness, and any admission of responsibility that is appropriate. Good luck with your parents.