It seems to me that it doesn't matter what college I go to, as long as I go to one as a full-time student I should still be on their insurance, right?
as long as you are in school for any 5 months during the calendar year, you can stay on their insurance - changing schools affects nothing - what does your brother know?
The insurance company couldn't care less what school you are enrolled in as long as you are a full time student.
I think you're right, but you should read the rents' policy very carefully.