Some snakes are just super shy and need to be housed in a dark enclosure to feel secure enough to eat. I had bought a female yellowbelly that refused to eat for me for a month until i switched her to a different rack without clear tubs. I left her in there for 2 weeks before offering food and now she doesnt miss a meal.
Also dont offer food to him more than once a week. If you try to shove food in his face every couple days, it will just make it worse.
Good luck!