River thinks he’s too cool for a lot of things these days, including hugs, good smiles, and so on. Ocean doesn’t have a similar issue (yet, hopefully he holds off a few more years since River started this a lot younger than I expected) and is always up for giving his brother a hug.
On many occasions at home River has said that Sunshine is the only one who can give him a hug, which is her cue to call for a group hug, which he protests over, but secretly enjoys.