character optimization getting loose be warned, don't bother reading unless you want to know how he could have done the quicken spell.
quicken spell makes it a swift action, after the errata, thus can be done without impeding all non-swift/immediate actions that round. Now Disintegrate is normally a 6th level spell and Quicken is normally a +4 spell level adjustment making it normally a 10th level spell slot, which is epic. I put all those "normaly"s in there for a reason.
Options to make it non-epic:
1) He could easily get it as a 5th level spell because it is 5th level for Duskblades, a few shenanigans involving learning spells from other classes needed but not hard at all.
2) He could easily take Arcane thesis for Disintegrate which would drop the metamagic cost of it by 1 for a particular spell.
3) Incantrix cheese, this prestige class and a few like it drop the costs of all metamagics for you by 1.
4) He could be a dragonwrought kobold and all the silliness involved in that and one of which involves a feat, don't remember the name off hand, that allows you to reduce metamagic costs as well (it is intended for dragons but hey your DW Kobold counts).
5) He could have easy metamagic feat for quicken making it only a +3 adjustment.
6) He could have used sudden quicken spell, works like quicken but no adjustment and only 3/day
7) He could be using another feat, versitile spellcaster i think, to allow him to use 2 9th level slots to cast a 10th level spell also.
ok now that i've destroyed any coolness factor i may have convinced people i had i'll return to just reading.
"People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf."--George Orwell