I managed to tame the 6 pilgrim goslings with a rather mistrusting mum, seeing she was from a free-range farm. Well, I´d just go into the pen with a big lettuce and she couldn´t help herself. She´d come over and the babies would come right up and eat the lettuce in my hand, then she´d grab a few bites too. slowly she became very easy and trusting. The gander´s been pretty laid-back from the start, so he was great as he´d bring the babies over to me. so, I don´t see why the same won´t happen with yours.
The ganders have a huge influence on the babies, and I find mine are fine once the babies are out of the nest and walking about. They hiss at first, of course, and kind of keep staring at me with their keen eye, but once they know I won´t hurt the babies, and that I have food, they´re fine.
I would think that Sam´s eating food from your hand will help things a lot. He´ll come round, I´m sure.
I was out there today with my 7-month-olds and 9-month-olds, and they come running up to eat of the food-pot in my hand, and I stroke them and scratch their heads. all parent-raised.