Does an unmarried couple, living together with a child, split their assets in a breakup?

Your brother's girlfriend has no rights whatsoever to anything other than the personal property she had when she moved in with your brother plus whatever she acquired by gift or on her own after she moved in. If they had purchased a vehicle and taken title in their joint names, that would be different. In that case whomever was going to finish paying off the loan and keep the insurance active would get the car. The main issues here are the custody of the child, the amount of parenting time the non-custodial parent gets and the amount of child support the non-custodial parent has to pay the custodial parent. I would suggest that your brother needs to file a petition for custody, parenting time and child support with the local Circuit Court along with a motion for a status quo order that directs that the child stay where the child is now living pending a final determination of custody by the Court. While custody of a very young child will normally be awarded to the mother, that is NOT automatic. Your brother needs to see a family law attorney before she leaves with the child. On another point, if she is on his bank accounts or credit cards he needs to move his financial assets to accounts that are in his name alone. Also, if he owns any guns he needs to store them with another relative somewhere other than where he is now living. This would avoid giving his girlfriend the opportunity to make a false report of domestic violence in order to get him expelled from the residence under a domestic violence restraining order.