I have something very horrible to say right now, but it is likely truer than not.
Your parents aren't very smart.
To spend, find you are out of money and spend a bit more is one thing, but to find that you are in debt and generating more is bad!
You don't go compiling debt, and/or ignoring it, that is a sign of financial immaturity.
By not telling you in the present and continuing to try and live comfortable lives on money they don't have, they have generated more debt, given you more concern than you ever needed and compiled the issue into one big clusterforget, that, realistically, they may never pay off, and may go onward to you.
Its not nice to consider, but it is sadly a possibility.
At the very least, they have generated a debt larger than some peoples superannuations. Its careless and not responsible behavior, and they have passed that to you by pretending to you that everything is okay and have placed you, for a long time, in the wrong financial mindset also.
On a lighter note, I wish you good luck. You really do deserve it. Try telling your parents about Bisjac's share idea, it seems like a good one, and would generate a long-term profit.