'He has suffered a broken nose, fractured eye socket and a concussion, while Stephanie was left with scratches to her face and allegedly suffered five broken ribs.'
That's shocking.
I'm police and, at least in my force, upon arrest a risk assessment for the 6 month old will have been completed and sent to our child protection team for review.
We complete these even if the child wasn't present during the fight.
CPT then refer on to multi agency team, including social services, if it's felt it's needed. (Which lets face it surely it would be in this case)