She deserves to pass this test.
This is probably going to come off as harsh or "meaner" than I intend.... but I don't understand this. An exam is there to show understanding or lack of knowledge on a topic. The people that "deserve" to pass are the ones that show
on the exam that they have that knowledge. If a person is failing an exam, they certainly don't "deserve" to pass, simply because they tried. That's not how exams work. No partiticpation trophys here.
With all of that said... I have a very good friend who has been a realtor for many years now. She helped me sell one house, and recently bought a new house. I can certainly ask her for some pointers. In general, for when I'm prepping for any exam, I look to see if there are practice exams online that I can take. Even if they don't have the exact, current questions, they generally will cover similar topics. At least enough to know if something needs brushed up on. Has you daughter in law sought anything like that out? I did a quick google search and came up with a lot of results that looked promising, and free.
If she's taken the exam three times already, I would think she would have at least an idea of which questions seemed difficult. Even without a discreet list of "you got questions 1,14, 20 and 43 wrong", there should be a general idea of "this particular section of the exam took me longer / was more difficult" should be an indicator that brushing up on that topic is warranted.
It could also not just be a lack of knowledge/understanding, but perhaps misreading the question(s)? It's not uncommon for "trick" questions, so paying careful attention to the wording of the question and answers (if multiple choice) can be pretty crucial. This would be exacerbated by a time limit too.
Is the exam timed? If so, when going through practice exams, make sure to stick to the same time limit. If the exam is 60 questions in 60 minutes, try to do that in practice as well.