After you file

Full question, claimed my disabled brother who started working last year and earned around 10,000 gross. Was told income doesn’t matter if they’re disabled. So I went ahead and claimed like I did every year and I checked the status of my return and it stated, “We have received your tax return and it is being reviewed. You will receive a notice from us requesting additional information within 30 calendar days. You may not receive all or part of your refund until we receive and review the information we requested. If you need more information after you receive our notice, call the number on the notice.” This hasn’t happened before and I’m stressed now! I was told by many tax experts that I was able to claim him and that I should be good and then this happened. What’s gonna happen when I receive that letter? What more info do you think they’ll need? What’s gonna happen to my refund? I’m panicking. HELP.