Posted: 10/01/2016 at 14:54
The normal way to propagate clematis is by cuttings, so you could try some of those to give your brother.
That said, if you have a huge clump and want to reduce it anyway - you might want to try chopping a chunk out. I've never heard of anyone doing it though. It would need to have a lot of decent root on it, and it may sulk for a while, but if you want to give it a try.... why not....
I'd take some cuttings as insurance anyway