IT is hard to explain.
The dua is quite personal, It is not impossible, if God wills it can happen. But the problem is, when i see the people who have gone through the same, i feel like it is a pattern and dua can't change it, Here is an example of what i mean by a pattern. For instance, there are two students who did not study for an exam, and attend it, Afterwards, one of them B starts making dua to Allah to help him pass, while the other doesnt. So do you think B might pass the exam because he made endless dua? or should he understand that since those people who do not study are bound to fail, so making a dua is of no use, and instead he should start making dua for something else,
It is not related to exam or anything, but the problem i am going through is a test and ive seen people who are not prepared usually, do not get affable results, but like i sd, by dua the kid might miraculously pass, even though it might make him lazy when it comes to studying and more reliant on making dua