Maybe you should treat the advice as one person's opinion. Also were they literally suggesting college level classes, or were they just saying seek advice from a college faculty member. In an earlier thread a few months ago you said your DS7 was in 5th grade math.
http://giftedissues.davidsongifted...._get_my_son_into_acceler.html#Post186434
It seems he should do a course sequence up to calculus (and add some discrete math) before trying college math or science classes.

If you're homeschooling a highly mathy kid, AoPS is the way to go.

I have no idea what to do for science and would love to hear suggestions.