Parents are also very busy. And, parents also do not remember all the lessons from school. Today's parents may not know the new methods or the new topics they are teaching in school these days.
Sometimes parents, and also siblings, will try to help a student by giving the answers. The idea is for the student to get a good grade, but the student is not learning. And the next time the student has to do this alone, the student will not know.
For parents and siblings to be good tutors at home, the important thing to remember, the most important part of learning is doing and then teaching back. Get your kid to practice what they are supposed to know, then make them come up with their own examples to show you,