Klmno,
I took Ativan for a while to help with some significant anxiety during difficult child-meltdown season. I found it had the following effect.
It removed all of the physical symptoms of the anxiety. Whatever was bothering me was still bothering me, but I wouldn't be all jazzed about it and could deal with life more rationally. It essentially mellowed me out.
I found that if I took it during the day it woudn't make me sleepy, just sort of cool and mellow and very very calm. If I took it at bed time, I would fall asleep within seconds of lying down.
It helped too well with sleep in my case. I became dependent on it and couldn't get to sleep without it for quite a long time.
The big issue with Ativan is that it is HIGHLY addictive, which is why the doctor is warning you not to use it too often. It's very easy to get dependent on it with regular use, and it's a real bear to wean off.
I would suggest giving it to difficult child on the test day itself, rather than as a sleep aid before or after. That way you're less likely to end up with disrupted sleep patterns or a dependence on the ativan to get to sleep at all (both of these happened to me, and apparently are very common with regular use)
If you stick to PRN for severe anxiety, it should be okay.
Feel free to PM me if you'd like more details. Hope it works for your difficult child.
Trinity