I took the HESI a week ago and found the grammar
portion the easiest. I got a 92 overall but my school only requires the Math, Reading, Vocab sections, although I studied for the science and A&P. (whew) I don't remember many questions about commas, but there were a few questions you had to identify the correct form of there, their and they're, its and it's. There were a few sentences that had the words from and form switched around as well as lots of questions about using the right tense of verbs, etc. The vocab was tougher but some of it was medical terms and understanding the difference between prognosis, diagnosis, subjective, objective, assessment, etc., etc. I hope that helps! Good Luck to you both!