I'll jump on board Detlef.
Ah, to restore or not to restore...always the question. Here are my thoughts on this one.
This has some really interesting native repairs going on. I especially like the wooden nails. Some interesting history there for sure. If this were mine i wouldn't change those a bit. I would simply clean it up a bit and maybe try to secure the pommel a bit if possible. You certainly can't remove the rattan and ever expect to get it back properly in place again. So i would clean up the blade and wood a bit and leave it be.
I really like this sheath btw.