Keep monitoring his weight. And double check husbandry. He hasn't lost enough to worry yet. I have had a female go off feed for nearly a year. Just kept offering food and weighing her and one day she ate and hasn't stopped. In fact. Last night a snake I got just before christmas ate for the first time. He was only half the weight your snake is so I was considering an assist feed. I tossed an asf hopper in with him and turned around for a second. When I looked back he was swallowing it.
Beautiful animal, by the way.
edit: oh shoot. I meant to suggest trying different prey items. asf's successfully got a snake eating for me in the past. I had no trouble switching to f/t rats after a couple live asfs got her eating again. If you can get them, try it it's worth a shot.