He knows she is the older dog - feeding her first won't do anything really.
If you want to feed her first, then feed her first - alone. Then when it is his turn, feed him alone.
He is insecure with his food around the other dog, but not you, that is ok as long as you manage that and help him build confidence by not having him feel like he might lose his meal everytime he eats. Also, get your hands out of the dish. Hand feeding, or using dinner as a reward is fine, but if someone had their hands all over your food when you ate, you might eventually reach out and slap (bite) them.
If you are feeding them together, put them in crates or on opposite ends of the room. Once they are done eating, they lay down beside their bowl until the other is finished and the bowls have been picked up.