Fuzzies are one of the easiest... but there's a risk one may never take to frozen.
Try leaving the tank lights off and use just ambient light for the moment.
Since I started using the ghost shrimp method towards the bottom... no one has beat me using it yet!.
I didn't realize you meant he hadn't eaten in two weeks... thought you were just concerned about him hiding. Ya, 2 weeks it about enough.... we gotta get something in him.
Training to Take Frozen
Right now, I would fill him up with live food. It's easier to train when they are hungry... but you don't want him getting weak. The guide also mentions a net method... you may be able to deliver live foods to where he is hiding.
If he doesn't take live.... make sure to come back here and tell us so we can go over what to do next.