When does college rescind the offer

She’s in a top 20 public school in the country that’s extremely competative and cut throat. Where all classes are either honors, AP, or IB. She’s getting an IB diploma. So getting those As was very very hard. So she’s beyond burrned out. I never had to push her to do anything. She always pushed herself. I have no problems with her taking it easy for the rest of the year. Just wanted to make sure it will be OK with college she got into. The acceptance letter doesn’t really provide any specific info. Just generic statement to keep up your grades.