I have done the compass test before;
- Flying the flight directors and the heading indicator along with the speed tape for a couple of minutes cant tell you much about a persons abilities.
If Alpha did change the results, that is not ethical.
What were the issues that came up in the core flying stage? If he did well in the groundschool he would have had his instrument procedures down before he got in the airplane. Was it the basic handling? Circuits? Radio Work? - All of these things can usually be fixed , especially if a person has the ground knowledge covered.