You said "he" in your post and that he was about 2 years old. It may be that he is just going through a fast that mature male sand boas go through. Mine all fast at this time every year. Each one is different with the duration but they all fast right around now. I have one male that will not eat from March to September without fail. In fact, if I can get 10 meals in him in a year it is a great year. If all other conditions are OK, I would just keep offering periodically. He will come around.