Not only that, but it also wouldn't be fair to either A or I. He is still young, still trying to find out who he is himself, and needs to have a life of his own first. He needs a chance to grow as a person away from the constraints of mom/dad/little sister. Work a full time job, explore and travel, pay his own bills, and just spread his wings. It would not be fair to him to have to take full responsibility for Abbie at such a young age. My oldest son is still trying to figure out who he is at 23 and just starting to carve out his own life with his own little family. He's taken care of his brother in a pinch and I'm sure would step up if needed, but his brother's care is our responsibility. As they both mature, I'm sure my oldest will be slowly brought on board to possibly oversee his brother's care in due time, but I also want each of them to have their own lives.