[ Nico is light as a feather and although Spike would fight tooth and nail to deny that this is anything other than a rare spot of decent behaviour for him, there's more to it than that. They have a few things in common. Nico knows a part of him that he himself can't understand most days and even more so, this is the best he can do to atone for what he did. That soul is searing a hole through his chest and this lessens the pain a little bit. Makes it bearable.
He continues to walk in silence, keeping the boy close until he can find a safe spot. Maybe even a dry spot where he can lay him down and then linger close by until someone else comes along to make sure Nico isn't left behind to drown. ]