My apologies, thought you were asking about my buddy who didn't get through, misread your post. I still think that how someone performs in IFS (or while doing their PPL) does not have a very good reflection on how they do in the fleet. Different aircraft, a lot more instruction, more time at the stick, yada yada. In my opinion, IFS should be what it is titles "Introductory" and by that I mean "Does this guy/gal WANT to fly? Is he/she prone to getting airsick".
Without standardization between the flight schools, or even the individual instructors, it makes it hard to justify IFS being a skill based filter. Talking to the IFS office, they informed me that almost everyone who has failed their solo, have all come from the same school. I am not trying to advocate that they are being "unfair", rather that there is an obvious standardization issue and even the IFS office knows about it
