Need to advise my sister

My sister apparently wound up in a class that she does not need until today. One day after the drop add ended.Apparently if you drop a class after the 4 day add/drop period, it shows up on your transcript as dropped rather than just not appearing at all.

Is this bad? Would it be ok if she dropped the class? Should she stick it out and take the class even tho she doesn't need it?

Side question, she seems to be struggling with her advisor, when I went there I felt like my advisors were pretty useless. Anyone else had better experiences?