Error on the Family Section

I have a brother who is in college and will graduate in 2021. In the family section I typed in his enrolment and graduation dates (which make it obvious that he is still in university) but I accidentally listed him as “Graduated from university/college”. I only realized this after sending my Common App to one college. Should I contact the admissions office and let them know? I fear that my application would otherwise seem fishy.

I think you’re overreacting. They mostly look at that section to figure out if you have any connections to the school and how much they might give you in aid. They’ll obviously see that his expected graduation date is in 2021, so they can do the math themselves. Don’t bother the offices, they’re super busy and this is kind of trivial.