The chances of you being pregnant are basically zilch. Sperm has to be deposited inside the vagina in order for you to become pregnant. Since you weren't interacting with his sperm or engaging in sexual intercourse, and especially because this all happened through clothing, I think it's safe to say you aren't pregnant. Your illness was probably picked up from your brother and it may delay your period, as might stress if you continue to worry that you are pregnant. If you're incredibly concerned you can take a pregnancy test fourteen days after the last time you were intimate and you should have an accurate result. Best of luck.