If he was a non feeder before, sometimes brumating will help, but obviously it's not a sure thing. It may take you a while to work with him to get him eating again. There are MANY threads on getting problem feeders to eat. Have you tried washing, braining, slitting, scenting, and tease feeding? You say he ate a week ago, but you don't mention if you had to do anything special to get him to eat. If he ate willingly a week ago, and refused now, I'd give him another week and try to feed normally again. Then if he doesn't eat, you can try all the other methods to get him to eat. I wouldn't stress too much, unless his spine is showing, he should be fine with a meal a week ago. Also, don't constantly offer him food, give him at least 5 days between offerings.