I don't have any gears you can have, but I've got a set of unused 8-speed spacers for £5 delivered if you're interested? Pretty sure you can use any Uniglide cogs with them and you can use Hyperglide cogs if you file the wider tooth down and a normal Uniglide lock cog or track cog.
Assuming he's already got an old worn one, are all the cogs actually dead? On the Uniglide you can turn the cogs round the other way and basically double the life.
I still have some odd used sprockets and a new 6 spd 14/24 cassette.The odd sprockets can go for postage costs,the new one £20 posted.Pm me if they are needed.hm.