What about pop a few joke scratch cards in his card, they are very convincing, he's guaranteed to win, guaranteed to believe he's won and you are guaranteed a giggle!:^O (I think you can get them on ebay)

£50 note wc roll:^O

On a more serious note! RC helicopter/boat

A couple of lottery tickets

Maybe ask family members for old photos of your brother and put them into an album/frame

Music cd's from his day:-)

If I think of anything else I will pop in and let you know otherwise good luck with that and let us know what you choose