I really cannot stress enough that Romano ISN’T the forgotten Child and Grandpa Rome loved both of his grandsons very much. 

In the scanlation of when grandpa Rome came to visit there’s a scene that didn’t make it into the anime 

Rome went to visit Romano too. 

In fact, he nuzzles up to him telling him “grandpa’s here” 

If that isn’t love then I don’t know what is.