Nelli_ said

Oh sorry! I seem to have left half the point out of the my post.

Charlotte gave Cormoran a walking stick in the first novel. Made of wood, used to belong to her grand-father or something of the sorts? And now Robin gives him one, made of wood, a very rough one, yes, but still a walking stick.

So is JK making a point of Robin "replacing" Charlotte in Cormoran's life/heart?

Charlotte gave him an aid that was glossy, too short for CB, heavy with family history - family which will never think Cormoran as suitable partner to Charlotte (or anyone probably).

Robin gives him a DIY stick while walking beside him on a rough path. And onward they struggle, together.  

Parallelisms of the stick aside (which, indeed, is addressed later), the most telling thing about the parallelism of the hospital scene was that there was NO Kairos moment. This gives the Strike/Robin relationship yet another quality. There is no "telling moment" but there is also no drama, no show, no big film moment, because their love is/will be steadier, more wholesome, less toxic.