Plus, well, Selene developed a liking for the baby herself. So, yeah. ;)
Of course, Selene can just be nice to the baby in her dreams and protecting her sleep, so it'd be sorta like the "chosen one" thing Venus has with Lilly.
Not to mention that the parent in question isn't necessarily too inclined to keep the baby (yet) and will likely, if all is the same, be willing to let Robert visit, take care of the kid and so on. Basically - ideally - a bit of a new friendship could be formed between Robert and the parent allowing Robert to care for the baby still. And Selene might well do so "backstage".