I'm not sure what your role is that you get to read the reports, and yet have apparently no understanding about why loving grandparents might want to read the report? I think that you might like to re-think your username? I am a reasonably educated person, and in your situation, the thought of a grandparent wanting to exert control over their loved ones, would have been one of my later considerations, rather than my one and only, jumped to decision. I also don't think that the OP's thread should have led a profesional, such as you claim to be, to such a conclusion, quite so quickly.
As a very loving mum and grandmother, I have never wanted to 'exert' control over any of my offspring, or theirs. But one of my Grandchildren has a serious condition that I do obviously ask about when I contact them. I am only asking out of love and concern for both my DGC, and their parents. I do not delve any deeper than that, and I just accept whatever other information they feel like giving me. Luckily, they keep me well informed, and although I live quite a long way away, I still feel as if I am a loved member of their family unit, in fact I feel very blessed!
It is not in my nature to ask for anything back when I spend time and energy on my family, in fact it wouldn't even cross my mind to do so. So, if the OP's MiL does expect repayment in some form or other, then I do think that that is awful behaviour. Unfortunately, so far, the OP hasn't said anything that makes me feel that she - the OP - is telling us the strictly honest truth, and with no exaggeration.
As, your reply @Savvysix1984 to the OP, was Imo just saying exactly what she wanted you to say, and that you included that nasty bite about her MiL to try to - and probably succeeded to - make sure that the OP felt warmer towards you and even more animosity towards her MiL, you are just not coming across to me as a profesional assessor, or counsellor, or therapist of any kind. So, I just hope that the OP can ignore your short, but mighty, words, and not let them influence her.
Neither you. nor I, @Savvysix1984
know how bad the MiL, or the OP really are, in my guts I feel as if the OP has exaggerated quite a lot of the MiL's traits, including that the MiL would gossip about her own blood family. I think the fact that her DH's family seems to be reasonably well off, is actually a slightly raw wound to the OP.
Of course @ladyrushford shouldn't share their DC's report if both she and her DH agree on that, but I don't think that in normal circumstances, it should be a definite no, from either parent, as they should discuss it just between the two of them, until hopefully they can reach a joint decision. Unfortunately, being human, means that if I was the DiL, or even the son, in this equation, if it truly did come as a demand to see the report, and with a threat on top of that, my answer would be a downright no, as well!