Hi Mindfield,
I didnt realize that you are still in your teens; you seem very mature for your age. I think your plan of action sounds very reasonable and probably has the best chance of getting through to your parents; if anything will.
I have found that casually putting just a little bit of info. out there and then dropping it or even walking away then is very effective. They can think on what was said without the need for a response on their part, and that often will elimanate the need for defensiveness.
Your parents can be very proud of you. You care enough to want to help as many of your relatives as you can and yet, you seem to be willing to be respectful of thier position. Hang in there, be patient. So glad you are here, I always enjoy your comments!
Sincerely, Windrider