The offers (or lack thereof) are entirely up to the universities - whether they make on or not is their business, and they have no obligation to make an offer to every student meeting their minimum published requirements. The strength of the "gathered field" of applicants varies from year to year and course to course, and it may be they had a particularly strong set of applications this year.
Equally, to my knowledge Edinburgh (and I believe Glasgow in a similar vein) note on their website that normally applicants will need to exceed the minimum (sometimes quite considerably) to make a competitive application. There is UCAS Adjustment for students who exceed the requirements of their firm choice - and Clearing besides that. I don't know if Edinburgh participates in either of these for any/all courses however. Finally there is the option of taking a gap year and reapplying if neither of those are applicable and he exceeds his predicted grades considerably, or going on to complete his undergraduate elsewhere and applying for graduate study at Edinburgh.
I would note an unconditional offer is very rarely given to students who have not year completed their qualifications. A conditional offer is the standard fare - but it is not guaranteed by any means even when meeting (or sometimes exceeding) the stated entry criteria, particularly for popular universities and courses (as suggested above).