Merlotgran, yes I believe Rob could make an application to the family court, arguing that his baby's future lies in his care, along with Henry. He'd no doubt argue that Helen launched an unprovoked attack on him and that for various reasons the baby's future lies with him. If found guilty, Helen is likely to serve a longer sentence than the 18 months she may be able to keep here baby with her. He could seek to persuade the court it's better the baby moves in with him rather than face life in hmp followed by separation from his primary attachment figure.
The family court won't make final decisions until the criminal court concludes. Nightmare scenario for Helen but if Rob is true to form and character, I'd be surprised if there isn't a contested hearing in the family court.