Butternut squash seems to be one alternative, another is Sweet Potato baby food. Keep an eye on the hedgehog, make sure he is drinking water and if he is not eating, you're going to have to syringe feed him baby food. I'm dealing with my Vera currently, she's still weak but is drinking and eating on her own, but hasn't become regular yet.
Hi we gave him some olive oil in his food and the next morning we had some success and he has been ok since. He is eating and running around so he seems ok.
He is a totally blind hedgehog so does come out in the day, which is understandable as he probably cant tell the difference!!!! Bless him