First off... Congrats to your Bro and his GF...

Hope theirs is a happy and long marriage...

Suggestions for a gift or two...

Maybe a bicycle built for two... Or if impractical or hard to get how about matching his and hers bicycles... With a picnic basket preloaded with blanket to sit upon and everything else needed for a picnic other than the food...

It's always nice to get away and bicycling is good exercise also... Picnic basket is a great excuse to get out to the great outdoors and away from the standard b.s. and stress of the cities...

Just my suggestion...