I've read hundreds of college essays. The good ones and the ones that quietly get rejected all have something in common, and it has nothing to do with vocabulary or structure.
The good ones answer one question clearly. Why does this person do what they do.
Not what they did. Why. Anyone can list achievements. An admissions officer reads thousands of lists. What they remember is a reason. A student who fixed up an old radio because their grandfather used to repair them. A student who started tutoring younger kids because they once struggled the same way.
If your child can't answer that "why" yet, that's not a writing problem. That's a Class 11 problem, and it's fixable, but not in the two weeks before the essay is due.