I can't really blame him/her. CS focuses mostly on discrete mathematics. While there are some required calculus courses in a CS program, IIRC they don't go up to diffeqs and most CS courses never really make much, if any, use of the calculus that is taught.
I can say, as a CS graduate, that I liked discrete math and hated anything in-discrete. I avoided statistics (as opposed to discrete probability) entirely.
